It's a pretty nice game to be your first game, also, the game finishes when you have shoted all the zombies, is a pretty short game, next time you can try to make a shooter but a bit longer, also good game!

More room for improvement.
This game is going no where with just one level
You could make it more interesting by letting the player move the character using the direction keys.
And you could take it to the next level by bouncing the bullets of the walls to hit the red thingy.
Good luck further.

Competent, but no replay value and the sound effects are atrocious. I see effort, though.