Well... Pretty basic, but well done. The difficulty is pretty good.

Really funny game.
Very simple but good, really cool to past the time.
And the great point is the score mark too, you did a good job on this.
Keep making games and improving more and more.
~DeadRises

pretty good for a first game if you dont know how to code

Pretty good for a first game, enjoyable and a good start! Try adding different colour combos instead of just blue and yellow, and double check next time that you have the controls properly labeled. Try adding a background, music, ect ect. But it looks like you put actual effort into this so good for you! :) 3 stars!

its the little things that count. its obvious to say that you have worked well to make this game and there is probably nothing extra to improve controls. you could , for instance make the transitions of the enemy waves shorter, there could be a life bar when you get hit by one, a bar goes down by one with power ups maybe and possibly put in a background with some sound effects. that will get you an awesome game! hope you see this review and build up this game into an even better game!! 4 stars because you deserve them