A breath of fresh air!

I jumped in and played a few rounds for the first time, here's a badly written review (i'm assuming you've read the modpack description so you know the basics)
Unhide the spoilers if you've already played the game since it's best played blind.

MOVEMENT
Just like vanilla except you have a midair jump, dashes, a wall grab/jump and Step (you can walk up blocks like stairs).
I don't find myself using the wall grab as often as I should, but when I do, it saves a lot of time.
Double jump off the bat is just a tiny bit op tbh, you can use it to survive huge falls it speeds you up a ton but I don't mind it staying as-is.
Having step from the get-go is balanced, doesn't make you too fast but lets you outrun mobs if you choose to go uphill.
Pressing alt + a direction will make you dash. In it's current state it's extremely overpowered.
You can fly across entire lava lakes by dashing repeatedly and then using your midair jump right at the end to negate fall damage.
I'm sure the dev will get around to nerfing it at some point.

GAMEPLAY
Escaping the nether is pretty simple, you get the equivalent of wood tools -> stone tools -> iron tools then you mine straight up.
It would be nice if there was a guide book that tells you that you're supposed to mine all the way up to escape.
Okay let me just interject for a moment (lol) - I found out there are custom advancements right as I was about to publish this review. It's not really mentioned anywhere, I completely missed them. (maybe the dev could make them more promiment outside of the advancement button).
The main difficulty seems to come from:

1. Trying to stay alive (the mobs are rough!)
2. Finding pyridium (the equivalent of iron ore)
   It took me way too long to realise that humanoid mobs can dig to your location, they really keep you on your toes.
   Food is pretty easy to take care of as mushrooms are pretty much everywhere .

COMBAT AND SKILLS
You have extra reach by default (only for combat) and knockback seems to have been increased as well.
The increased reach + knockback means juggling enemies is way more effective than waiting for your weapon to come off cooldown. (dev has noted this and will fix)
Since spam clicking is the meta, and since you will rarely encounter swarms of 4+ enemies, the AOE sword attack is kinda useless.
In the skill book you spawn with, you can swap your XP and "Souls" into minimum wage skills!
I realise now that the skill book tells you to use the arrows on the bottom left and right to flip pages but I completely missed this (maybe add an outline to the buttons?).
I'm honestly not a fan of the skill book and rarely ended up using it. It's just not necessary since it's easy to escape the nether without touching it. This might not be the case for the other dimensions. (dev has noted this and said the skill book will only be available until you unlock something in the later dimensions)
I didn't play with the skills much due to this, but upon reading the skill descriptions, they seem really powerful. Especially ranged skills (allowing you to fight lava spewers without crafting a bow/arrows) .

PROBLEMS/COMPLAINTS
I found myself wandering around quite a bit trying to find pyridium, then i realised it can look just like neridium if it's in the dark (maybe change this?).
Step: it's useful but quickly gets annoying as i can't find a way to toggle it off when i don't need it.
Fire: No way to mitigate this early game which pretty much makes it a death sentence. inb4 skill issue.
Mobs drop loot which is nice but they drop a bit too much + it's enchanted, idk i feel this made it too easy (they drop lots of garbage loot as well which just clogs up your inventory).
Sometimes mining dirt with a pickaxe can result in a whoosh whoosh whoosh sound as if i'm hitting the air, it's just the sound that's bugged, mining works.
Flame spewers are OP af. Could be by design, requiring bow/arrow to counter but this makes bone harvesting very unviable since they take time to acquire.
Magma eggs and dark wheat are essential items for bone harvesting (30 sec fire resistance) but I have found no way to obtain them.
Dashing. I mention this in the movement section.
It's easy to be unaware of the advancements which give you hints as to what you're supposed to be doing.
That viney stuff that hangs underneath blocks, yeah it adds to the atmosphere but man it gets annoying fast.
Cannot view detailed info for skills until you buy them.

THE GOOD STUFF
Controls are pre-configured for you! Man, the polish that adds to a modpack cannot be understated.
The last thing you want to see when you install a modpack is a billion unconfigured/conflicting bindings.
The visuals are stunning. Glowstone and leaves glow a little too much but everything else adds to the atmosphere greatly.
This is one of the few packs that uses sound design very well, it's hard to tell if mobs are close or far away.
that + spooky music = :skull: :poop:
A quick "Reset Run" button to start a new run once you inevitably fail. You will become very familiar with it.
The level generation is great, it's not the modern nether, it's the old one but with lots of polish.
Balance. Despite what I've written in this review, the modpack is pretty balanced overall, mobs are fun to fight and it's action packed.
Novel gameplay! Finally, a combat-focused pack that gives you a timer, a goal, and leaves the rest up to you instead of slapping you with a guide book that has a billion crafting quests with the same old formula we've seen many times before.
Replicating the vanilla-like progression is something I really appreciated with this pack. I could realistically see speedrunners doing the rounds with this and optimising their strats just like with vanilla minecraft.