Honestly, this definitely needs improvement. I understand that this was made in 48 hours, so the fact that the game is in as good a shape as it is shows your skill as a developer, but I still feel that this is not the best in the world. I suppose the biggest problem is that lack of audio. I still don't know if that was a glitch, but if it was not a glitch, you definitely need something, sound effects, at least, but the fact that you say you're still working on it assures me that the audio issue will be fixed

Another issue, for me, at least, is the combat. I never feel like I can kill anything. I feel like I will die if I even get into the line of sight of a gunner. Plus, with the knife, when I approached an enemy, I always took a hit. It was nearly impossible to get a clean kill unless I had some bullets. Maybe some more of a tell for when an enemy is about to attack, or something that can clue you in would help, I feel.

My last problem is mainly due to personal preference. I really don't like the color scheme. Again, this is completely due to personaly preference, but I like brighter colors than grey and brown in my games.

That said, it's not all bad! What I managed to see of your level design seemed pretty good. There are a good number of vantage points for the gun, and the actualy graphics themselves, colors aside, were pretty good.

I actually made a video, if you'd like to see it.
https://youtu.be/N8895GYawYc