Pretty cool game in some way. Just wanna say something about obvious problems I found. I don't want to offend the author of the game (His youtube channel is pretty nice. I like it for videos about making 3D models in PS1 and N64 style). I hope that my critique will be helpful for the creator and everyone who reading this.
1. Game part.
1.1. Game has a small contradiction in some mechanics. It's not scary for the game but strange in some way. Haven't you noticed that? Try to guess by reading following facts:
a) The player's health decreases over time;
b) When the player completes the level all his characteristics stays at the same state;
c) When the player dies he starts the level again with the same state of all characteristics which he had at the start of that level.
Got it? If you complete current level with enough small health you won't be able to complete next level because you won't have much time to cure yourself. After your death you will be in the same situation because your health will be restored to the same state as it was in the beginning of that level. Over and over. It's like some of those situations where you save your game right before the player dies.
It's not scary because the game is small and easy to complete. If the game was big and difficult then players would have to restart the whole game in such situations, as I did when trying to reproduce given problem.
It can be fixed by restoring the health at the beginning of the level a little bit if its value is enough small. This isn't the best solution but it can solve the problem in some situations (Not all situations! Try to guess what will happen if player doesn't have something to cure himself from the last level).
1.2. Not good that player can complete most of the levels without using methods which were given by developer. You don't need to use gun. You can just run through the level maneuvering between the monsters.
Maybe it's not true but I think that developer thought the same and decided to add "hard" level at the end with 5 monsters in tight corridor with a lot of bullets for gun in it.
2. Visual design.
2.1. In my point of view background needs some interesting details. Simple rectangular walls and white floor contrast with the visual of main game objects and inventory.
3. Sound design.
3.1. Pretty good sound design but for having some atmosphere in the game it needs to have more "deep" (?) and "living" (???) sounds in it. Maybe some music. I mean that youtube video of making that game has such music that can build horror atmosphere in some way.
4. Level design.
4.1. The same as visual design. One level has one little joke in it (the end of the level is near to the start and you can't go there due to the wall in front of you). I don't mean that level design must have more jokes but it has to contain more intersting details, as I said for the visual design. Of course if the game was supposed to be detailed in such way by the author.
Conclusion.
Game is pretty cool but it has some flaws that can be forgiven due to the fact that it was made for Ludum Dare in 2 days. Why did I write this review? Because I love doing such things. And mostly important because that critique of small games can be helpful for making big games, in my opinion.