I only got up to the latter half of the second stage before giving up. The dog guard at the start of that stage is really hard to incapacitate. I ended up just running past it. You also have a stray tri along the wall of that stage passed the first guard that has collisions.
There should probably be some sort of suspicion meter. Guards become immediately alert at the slightest glimpse of the player if they're not sneaking. It feels unfair.
Sneaking feels jank. Sometimes it's OP and I can walk almost up to the face of the guard (maybe because it was a penguin?), other times it's basically useless. Consider adding ways the player can interact with the environment to obscure themselves with too.
Definitely feels like an early build. Needs to cook more but has potential. The environmental art of nolgorb was pretty good so I think you can pull it off.