This game is half-life-ish in every good way. Insanely good 👏
The enemy behavior should be more predictable, it's annoying when you die to an enemy who just out of the blue decides to turn around (especially also goes for the auto gun in the last puzzle, it's just luck to time it right from what I understand).
Also, getting hit by enemy bullets is pretty unfair as the bullet often gets you although your character is by far already out of the way, climbing up an edge.
But that's just minor issues, overall, this game is over-the-top good. Congrats!