The gameplay is not in any way engaging.
You got points for the music and the fact that it was in black & white, but there's no real game here. All you do is memorize where to stand as the drunken robot follows its pre-set pattern forever.
Here are some suggestions on how you could transform this game into a good game:
-One shot to the head kills the enemy, and there's more than one enemy.
-When a bullet hits the player or a bad guy, the bullet disappears at the point where it hit flesh, and there should be at least a burst of blood or a sound effect to indicate a hit.
-They pop up, aim at you, fire, then hide again.
-Killing one enemy should be easy.
-Surviving the entire wave should be hard, but not impossible.
-The player should never wind up in a situation where, through no fault of their own, they MUST take dammage.
-Enemies should react to the player's behavior, not follow pre-set patterns.
-Surviving one wave of enemies should take about 30 seconds.
-After a good, solid wave of combat, the player should get a chance to take a break. The player chooses when this break is over. It could involve a shopping menu, a "STAGE CLEAR Press any key to continue" screen, the word GO -> flashing while the game waits for the player to walk through a door, whatever.
-When the game resumes, there needs be something new. New background, different enemies, new weapons for the player to use, whatever.
-Power-ups are fun.
-Scavaging for limited ammo while you're surrounded by deadly enemies is NOT fun.
These are all fairly common concepts in video games. And given what's already in the game, I don't think you'll ahve too much trouble implementing them. You can IM me if you have any questions about coding, but I think you know how to code pretty well. Your design just isn't much fun. Refine it and try again. :)