Nice player sprite, though I'd try to add some more frames to that walk animation. 

I walked around the level for five minutes. I went to the left, to the right, but did not find anything. There are weapons in the game, it is not clear who to shoot at and there are no signs that would show where to go. And it also seemed strange to me that shooting is controlled by the mouse, although you can only shoot in two directions. I think it's pointless.

It seems like you there was a lot that didn't get implemented. It happens though, but I'll only be able to give you general feedback.

• The first thing I noticed was that controls weren't listed on the gamepage or in the game. At the very least, I would make an effort to do that in the future.
• While I find the player art charming, it doesn't fit anything else visually because there's no other pixel art. Just shapes. Don't get me wrong, basic shapes can look great and I used them in my last MVM entry. I would try to be consistent.
• I think you should put some time into thinking about level design and player feedback in general.

Overall, don't give up.