I liked the music and the vibe it created for the game. Game itself was very short and just one enemy to kill was a bit lackluster (Or then somehow I was able to get to the portal without even seeing them), but good artwork and submitting a game that works is already a win! :)
I think the bullets were way too small, I didn't even see them at first, until I was inside and tried to shoot the gas canisters :D Also the enemy could have made some sound effect or some kind of other marker (flash light or something) that I would know I was hitting him.
End of the level I just jumped out of the map, but I understand that this was just a demo and it was the end, so I didn't mind it all! :)