As many other reviewers have said, this pack is an outstanding example of what integrating mods means. Almost no mod hasn't been configured to fit within the structure of the pack. I remember playing this pack and being amazed at how fluid the progression feels at the start. This pack was one of the most important packs of its time and showed what was possible through mods such as game stages.

Unfortunately, this pack does suffer from some execution issues, with later ages feeling a bit like a slog and some changes, although cool, ending up more as a time waste than an interesting mechanic. While it can get frustrating sometimes, this pack is far better than anything similar to it that came before it, and it is still one of the best examples of stages in a pack ever made.

I did end up dropping this pack after progressing quite far because I just couldn't find the motivation to keep going, but the start of the pack was still an incredibly enjoyable experience and I find myself playing it sometimes to get more ideas about what I could do in my own packs. if you're a pack maker, I would definitely advise playing this to see what is possible.

I would advise everyone to try this pack, some of its mechanics hold up incredibly well even with it being over 8 years old as of this review!

Wow, Sevtech: Ages is absolutely incredible. I'd say it's one of the best beginner modpacks too.
It's basically a giant, fun, and engaging tutorial for every single popular 1.12 mod. I played it when I didn't fully understand a lot of the tech and magic and dimension mods, and it helped me every step of the way. I promise you it isn't holding your hand or full of tutorials, I just think, in hindsight, it's an incredibly good teaching tool for mods and modpacks.

Sevtech: Ages just keeps you playing so much longer than any other modpack. It gives incredible direction, every step of the way I feel like I am building towards a better minecraft world. Quests feel fun, and every quest and progression step in this modpack leads to more fun quests, tools, and technology/magic you can do and use. There was never a point where I felt like I was overwhelmed or bored or didn't know what to do next.

I could write pages about the fun and memories I've had with friends completing this modpack, but I will spare you all.

Go play it if you haven't. It's a fresh take on the modern 1.12 modpack and incredibly fun, well made, and well polished. Highly recommend.

To me, the best representation of Sevtech is that Endermen begin spawning after you already have to have built a smeltery in the game's progression, and have been tweaked to drop ender dust, rather than ender pearls. Ender dust can be put into a smeltery to melt into molten enter, which can then be cast into an ender pearl.
Why?
For what purpose?
It would have been easier for the developer not to change the enderman's drop.
It would have been easier for the player to not have to do these extra steps.
It would not change progression if endermen dropped ender pearls.
Why would anyone have done this?
What thoughts must have been going through the mind of Sevtech's creator to have ended up wasting the player's time like this for actually no reason?

Too few modpacks have a clear and singular vision the way that Sevtech does - It's beautiful, I love to see it, I hope more modpacks aspire to this level, and I hope that the singular vision they have is better.

One thing that stands out, with Sevtech, is just how little it cares about your time. Darkosto really looked at the thing in vanilla where you put your stuff in the Furnace and go read a book or something while your computer's running and said "that's amazing, I want that!"
Because progression is largely in a straight line, rather than giving you several things to do at once, I often found myself in the position of, say, needing Buffalo teeth to make the next piece of tech, and waiting around for my buffalo to breed, then grow up, then breed again, until I could afford to lose a few, or starting up a coke oven and needing two stacks of steel or three arc furnace electrodes to do the next thing in the list, so just having to wait for it to slowly process stacks of coal.
The Geolosys ore clusters are an interesting feature, but because they replace vanilla ores, rather than supplementing them, this was a minecraft where you don't really go mining, which I can't say is really what I come to MINEcraft for.
Now, these things were not what made me give up the pack, that was forcing me to interact with Pneumaticraft, even I have limits, but make no mistake - there was good stuff on the way there.

The amount of work put into this pack is mind-blowing, so much stuff that no other pack would dare to tweak is configured, even mods that have practically zero actual documentation, which I don't understand how Sev themself managed to configure, but looking in this pack's configs for examples is pretty much the only way that other modpacks make use of these mods.
Sevtech is supremely annoying in its insistence that you deal with mods like Pneumaticraft, Abyssalcraft, and Primalcore, it redesigns huge swaths of the game into something unified and interesting, with all kinds of reworked recipes, and yet still suffers from that kitchen-sink pack thing where non-vanilla resources are worthless. Primalcore fills the nether and end with plant fibers and clay variants, and they're not good for anything whatsoever.

Idk where to fit into the review that Primaltech is really cool and I love using it.

In spite of everything, Sevtech is a really impressive showcase of what modded MC can be and do, and I love to feel like I'm experiencing a creative person's unfiltered vision, even if that vision is practically the opposite of what my own would be.

Foreword

I completed this pack about a month and a half ago, but with playtime split over the course of about a year and a half. It took me about 262 hours to complete the pack, with an estimated 15 hours of that being AFK. Some details about the early game may have escaped my memory given that it was quite a while ago that I played through it.
Also, I made a few tweaks to my experience, being that I added the Comforts mod, but only for hammocks (Astral Sorcery is a bit annoying to do if you can't skip daytime), and I cheated in the two paper clip singularity singularities needed to beat the pack (for reasons I will get into later).

Also this is going to be a long review, with a TL;DR at the end.

SevTech!

SevTech: Ages is overall a fun modpack for those who enjoy tech and some exploration (though mostly tech). The concept is really fun, going from caveman to space faring explorer, and it's also executed fairly well. The mods included are mostly good additions and implemented well, with only a few feeling arbitrary. There are however, some occasional design decisions that I find to be a bit odd, though they mostly are not a big deal up until late game. And speaking of late game, I think that it is where the pack falls off.

Ages 0-1/Early Game

The early game is very solid IMO, with a unique start compared to your typical pack. You start out gathering sticks and stones from the ground, shaping logs into makeshift crafting tables and being rather limited in the things you have. There wasn't anything that I found particularly bad about ages 0 & 1, with them being overall enjoyable. A big compliment I have is that this portion of the pack feels very unique, being fairly different from any other pack I've played or watched.
Totemic rituals are a bit awkward/confusing at first, but you only need to do a couple of them, and the totem poles from the mod are nice enough that I feel like the mod isn't a completely negative inclusion. I'm not huge on shoggoths from AbyssalCraft, but they're tolerable enough.

Once you get to age 2, you're doing some more advanced stuff, and going to more places. This is where each age gets longer than the last, the training wheels are off and you start to lock in and work on bigger projects. More blocks, more tools and more conveniences will likely have you establishing a more concrete base, though you may want to wait until age 3 for larger scale construction.

There are many things I like about age 2, but a few things I don't. Starting with what I like, you get a good chunk of new materials, tools and whatnot that give you more freedom to expand and explore, but not so much that you're overwhelmed or that you have everything already. Tinkers' Construct is a good inclusion here, as it almost always is in a pack (I love TiCon!), and this is where you get some more options for tools. I also like Astral Sorcery here, and age 2 AS is where the most notable tweaks from the base mod are.

The thing I'm not a huge fan of with age 2 is the dimension exploration. The inclusion of The Betweenlands and The Twilight Forest feel rather unnecessary if you ask me, as they feel too disconnected from the overall theme of the pack. These mods break up the pacing a bit, but given the progression of the pack restricting stronger gear to later ages, the pacing could be worse as you're at least not blowing through the dimensions with gear far stronger than what the mods were balanced for.

I did not enjoy traversing through the dark and tedious to navigate Betweenlands for the sole purpose of getting a couple gems to make a smeltery controller and one other thing I forgot. I will say though, the Betweenlands does at least let you get around the need to light torches after placing them via sulfur torches, which is nice. Thankfully you can bypass the dimension's tool restriction mechanic with Tinkers' tools.

You have to play through about 60% of the Twilight Forest just to get to age 3, and then afterwards you never need to go back there, which I'm not a huge fan of. Thankfully, you can use a slimesling and slime(blood)boots to get around quickly, but there's still a lot to go through, and it's likely that you're going to have to clear at least 2 crimson towers to get enough burning tears. I spent at least half of my age 2 playtime in the Twilight Forest.

While I'm not the hugest fan of needing to go through so much of the Twilight Forest, I'd be lying if I said it was all bad. The Twilight Forest was still pretty fun, if a bit too disconnected from everything else, and you can get some good stuff from there. Steeleaf is pretty good, as Tinkers' tools made with them will repair themselves if you have steeleaf in your hotbar.

Age 3

Age 3 was my favorite age, as I found a new love of Astral Sorcery and Immersive Engineering, and this is where I built my full base. To be honest, not too much was changed about AS and IE here, but I feel that the way they fit in the pack is just really solid. Like with age 2, age 3 is longer, with more gear, machines and whatnot from various mods becoming available. I spent a lot of time in age 3 doing things that weren't necessary to complete the pack. Building, exploring AS, checking out neat things from mods I hadn't used before and getting improved gear. Age 3 is basically just age 2 but with a bit less exploration/travel, and more tech & base development. You still have places to go though, as you unlock the nether and new metals you've gotta go find.

Age 3 isn't anything too crazy, but it feeds you a second helping of content and goals that are well paced and fun to complete. The only things that I don't like here aren't too big a deal. I don't like the mod Steve's Carts, though you're not actually required to use the mod beyond a few materials from it. It's a good thing that you're not forced to use the mod, because it has a bafflingly bad design decision of using cart assembly time as a balancing lever. This makes no sense and is just annoying, and it's the reason why I didn't use the mod.

Age 4

The differences between age 3 and 4 are basically the same between age 2 and 3. Age 4 has less exploration, and focuses even more on tech. While age 4 isn't bad, it does have a higher amount of somewhat tedious processes and odd design decisions.

One thing that totally confuses me, is the fact that the advancements point you towards making a Cooking for Blockheads sink, but then it's configured to not act as an infinite water source. I don't get why all the way in age 4, you finally get access to the sink, and the advancements suggest making it, only for it to be used for making food. By the time you reach age 4, you'll have undoubtedly found a stable source of food, so you don't need a sink for food crafting. Also, given the fact that in most other packs the sink is used for its infinite water source functionality, I was misled into thinking it would be the same here, which just made it all the more annoying that it doesn't work that way in this pack. What's even more baffling is the fact that there is an infinite water block in the pack, but it's only unlocked in age 5 and is incredibly expensive. Such a block being so expensive makes no sense since it's really only QoL, as you can pump infinite water from an infinite water pool which is effectively the same but slightly less convenient. The only reason I can think that this was done is because there's a design decision to have water not be infinite outside of rivers and oceans, but this doesn't really matter since pumps ignore this and you can just pump into a tank to fill your buckets.

There are a handful of other odd decisions like that here, but they're not really too big a deal. The main complaints I have about age 4 have to do with things that are annoying in included mods. 1.12 Pneumaticcraft is not that great IMO, being a bit janky and just weird overall, but you've gotta do a handful of it to get through the pack. The AE2 inscriber is also kinda annoying to use, and the ender alloys are a bit wack to make.

Age 5

Oh dear god age 5 is torture...
This pack is really good up until you get ~10% into age 5. The start of age 5 is fine, upgrading your infrastructure to use Mekanism and AE2/RS, exploring the moon and mars, but after that it's awful. Age 5 easily constituted half of my playtime on this pack, and I really only enjoyed a small portion of the age.

The main goal of age 5 is gathering a ton of materials (20k of each) to turn into singularities to summon the final boss. You are given methods to obtain these items in bulk, but not all of them are created equal. You have Environmental Tech ore lasers, Mystical Agriculture, RFTools, Industrial Foregoing & (some of) Mob Grinding Utils to help you out.

EnviroTech is good, besides the fact that you have to spend a bunch of materials and wait like 10 hours in game to get enough crystals to start upgrading your lasers to the point where you're actually getting a notable amount of resources from them. The wait was god awful, but I really enjoyed setting up logistics for processing the ores my lasers produced once the lasers got going.

I liked setting up some of the things I needed for the singularities, like Mekanism ore quintupling, a cookie farm, logistics & a manyullyn alloying setup, but most other things sucked. The resources that required MystAg sucked, because unlocking MystAg sucks here, and setting up MystAg automation is not fun at all as it's just garden cloche spam. I didn't like doing the player mob farm, though that's probably due to the fact that I left it for last and chose a bad method of farming them.

This pack showed me my new least favorite mod of all time: Extra Planets.
Oh my GOD this mod is so bad, and this pack doesn't do anything to alleviate it. Extra Planets is a Galacticraft addon that adds more planets, and you need to go through our solar system all the way to Neptune to beat the pack. This mod is so horribly designed that it feels like everything it does was made to piss me off. There's enough about this mod that I could make a whole post about it, but I'll stick to some of the key points for the sake of brevity.

So Galacticraft has these alloy plates as a material with three tiers, each of which being crafted with the previous tier. This works for the base mod, as there are only three tiers so while it's not the most convenient to make, it's not to the point of being tedious either. Extra Planets looks at that and decides to add SEVEN more tiers of these plates. As soon as you hit the EP plates, they just get incredibly tedious to make, and you have to make them again and again each time you want to go to a new planet. And you're not even doing much on the planets themselves, as all you do there is dig for ores for a while then leave. Space exploration could be really fun, but with Extra Planets it's just not fun at all and ends up being an incredibly tedious chore. And by the way, you need to go through all that planetary pain to get Mystical Agriculture, so you're going through pain just to get some boring plants.

One thing I do not understand, is why the paper clip singularity singularity exists. To make a singularity you need 10k of the respective item, and to beat the pack you need 2 of each singularity, so 20k of each item. One of the things you need is the paper clip singularity, with paper clips being made from meteoric iron. This is fine, except for the fact that you also need paper clip singularity singularities, meaning you'll need an arbitrarily high amount of meteoric iron to beat the pack. This would honestly be fine if it was that you could get meteoric iron from EnviroTech lasers, but you can't. The only reasonable way to get bulk meteoric iron is through MystAg, which is still super slow and boring. This is why when I beat the pack I decided I would get every other singularity then cheat in the paper clip singularity singularities.

Misc. Stuff I Want to Mention

I like the inclusion of Geolosys, and how you unlock more ores each age. I personally wasn't a fan of the "realistic" heat distribution biome mechanic, as I felt that it just made certain biomes more inconvenient to find and leaves the world feeling like there are only 5 biomes that are all ugly.

TL;DR

SevTech: Ages is a great pack up until you reach age 5, at which point the pack gets rather unfun. The pack is good if you like tech, and a decent helping of exploration. There's nothing too crazy going on here, but the pacing of the pack and how it introduces each mod is very solid. If you want to play this pack, I recommend playing up until you land on the moon which completes age 4, then call it quits there.

Difficulty is okay, not too easy but also not too hard.
It could have work better on modern machine where modpacks which has 500 mods + shaders have worked without any drops.
The most frustrating things are schemes of crafting which not tell why this kind of type thing won't do in this recipe - you have to guess which kind of wood it has to be made - name is the same like every stump which was made of wood.
Also guessing how to use kiln and fire is another level of magic thinking.

I had expectations which this modpack didn't meet at all.

Really linkedin the progression. One of the best. The small details everywhere are perfection. The lock of the progression between the ages are so nicely made

The fact that you cannot turn off the step assist mod (that makes you climb blocks automatically - basically auto jump) without progressing to a certain point makes this modpack unplayable for me. It's beyond me how anyone could think it would be a good idea to prescribe basic player movement options. It's a shame because the content otherwise looks promising.

The ages system is really well handled, introducing new mods, mobs, ores, and mechanics in a very enjoyable drip-feed of content. It really feels like a similar system to terraria, for the first couple of ages, and in a very good way. Some of the later ages (namely, most things post-plastic) are not quite so fun given the high resource costs and relatively inaccessible automation, as well as the fact that you begin to run out of places to explore and the content well starts to run dry.
There are some less enjoyable parts of the early game, namely most of the biome hunting that has to be done, though you eventually get through it and it's not so bad. Absolutely love the pack otherwise though, feels very cohesive!
Highly recommend playing this on a server with friends.

SevTech:Ages sets a high standard for all progression-based modpacks with its seamless progression between thematically different mods, as well as its effective use of the GameStages mod to create an engaging experience for players of all skill levels. I personally found the early-to-mid game most enjoyable (stages 0–3 and 4). I felt like the pack became more tedious towards the end, however. Playing SevTech:Ages is fun, both alone and with friends.

When people talk about 'integrating mods into a pack', this is what they mean. Instead of "hey, you just unlocked Blood Magic, go play that for four hours until you get this item", this pack says "hey, you just unlocked Blood Magic, go grab these items from these other mods so you can use Blood Magic to make this item from a different mod so you can progress a little further in a third mod", and it does this for every mod.

Performance suffers a little whenever a complex CraftTweaker script fires, but this only happens on Age transitions, so just grit your teeth and then revel in your newfound power.

The last chapter isn’t worth your time, and mods like the Twilight Forest aren’t so much integrated as they are used as a rudimentary time gate, but overall the experience is solid.