This game has an interesting concept, but I would agree with Lazarwolfe. In order to aim directly at an enemy you have to move your character in such a way that the character's body blocks your view of the enemy you are shooting. You could probably fix this just by moving the camera up a little, so that the player character isn't in the center of the screen, and you can see past him
Another thing that could use improvement is the feedback. Sound effects add a lot to the experience you have in a game. I would recommend adding a sound for when an enemy is destroyed, when the player is moving, and when an enemy spots the player.
The game's retro shader is good, but there just isn't very much to look at. Having a few simple decorations on the walls or the floors would make things better.
One last suggestion. It would make things more interesting if a few of the enemies moved back and forth, or looked around while they were idle. This way, the player would have to carefully time when they attack.
This game has potential! Thanks for submitting it!