i think it should have some achievements, because it is rapidly finished, it could have the achievement of mad scientist, that would be a little hard, because this game is rapidly finished.
it could have some achievements like getting badges or those things, just like the infectonator: world dominator, it would make the game very better, and i would play it more times.
too easy, too easy, humans they can't beat me!!!! Muahahahaha[...]
Humans, pathetic beings, the power of my zombies is great, i comand them, and they destroy even... spiderman, hehe, santa brings.... virus instead of presents... i don't know if in the game, hehe, you'll all be doomed when my zombies come, hey, i have hints for this game, make more of those soldiers, and those guys and make more cities per continent, it would make the game a little harder, ahhh, i have one more hint, make a difficulty select screen.
level 5 is impossible... you could make it a little easier, and you could make a little better the game, and, it's brazilian portuguese here, thanks, i'm a brazilian anyway... it's a mix of brazilian and english... make a languague select screen, it would help...