Really bad game, really good concept. Manual reload = fail. Manual reload doesn't reload = fail. Randomly hop over barricades = fail. X doesn't work to hop over barricades = fail. So, 1/5. Fix those and this would probably be my favourite game.
I kinda liked this game. I mean, it was decent, but kept me playing for a while. It looks like you didn't full complete it (All three towers say that there is a possibility for poison, but there is no tower with poison) so I'll give it a 3/5.
Oh, nevermind... I had 8 windows open at the time, and the lag killed me :P VERY easy for the shotgun and moderate with the rifles (First try without lag)
And, I also lose lives randomly, when the wave hasn't even started, sometimes explosions don't open up the metal balloons, holding down the speed button hurts my finger and drives me crazy, and the towers are also un-targeted when you move your mouse off the screen. If all those things were fixed, I'd give it a 5/5