Lol, first time I see a pixel game lagging as hell... 5/5 just for the performance, and for the fact I loooove upgrade games, of course...
Really unbalanced game (didn't buy last weapons, had to stop repairing to see them), no speed button (had to wait thousands seconds for waves), options are useless (thinking of shootgun, first aid kit, same for the upgrade...) Well, 5/5 luckily for my passion of upgrade games. That's all
Too much bugs : orbital shoots only ennemy, fighters are going reverse, can't upgrade army enough to fight ennemy, boring to stop every 10 sec... Well, too bad we can't evaluate a ZERO
Well, it's the tutorial he posted, no update or something... Even the map is the same. Good Job !
http://flash.tutfactory.com/games/tower-defense-game/