Thank you for the feedback !
1) I admit that I was a bit lazy with the sound in this game, because I tried to create my own audio melody and I usually use Bosca Ceoil for my games, but in this case Bosca Ceoil is better either for horror games or for games retro. The gun was later added when I saw that most of the games in GameJams had this requirement fulfilled.
2) I was thinking of putting a timer, but which can be activated optionally if the player wants this (there are also cases of players who want to be safe and wait until everything is well lit so they can jump).
3) Thank you very much! I created the last special level as a kind of "bonus" for the players and to give them a different atmosphere of the game.
4) I admit that restarting the level is a bit slow, but this is to give the game a more interesting aspect, but I suppose I can add an option in which the player dies faster if he wants.
5) Yes, I have received problems related to level 2. It's a bit difficult to do, especially if you don't know what the platforms are (as the creator of the game, it seems easy to me, because I know where the fake platforms are). To fix the problem with level 2, I will probably replace it with a level quite similar to level 4 so that there are no future problems (these in a future update and if there are more requirements).
6) I'm glad to see that most players love level 6, my only fear with it was that it wouldn't be considered too hard. I'm glad this wasn't a problem for you.
Thank you very much once again for giving the game a try and for finishing it. :)