Pretty simple but fun FPS. Pretty rare to see in game jams.
I enjoyed the visual overall thanks to the post processing effects, but there are some spots where it doesn't make much sense like the text is also super pixelated so you have to get really close to it to be able to read it somewhat.
The room layout got a bit boring after a while though, since there's only so many. But I think it wouldn't have been as much an issue if the game was a bit shorter. Not sure why you chose to make the game that long when there's not much content to pad it out.
Also not sure if it's a bug but I didn't see any changes on my gun after I buy attachments, so I didn't see any of the upgrades. I also thought the upgrades itself should come earlier in the game so it's more immediately fun for the players.
I like the audio and gun sounds overall, but not sure why wasn't there any music in the game levels itself, when there was in the main menu.