REALLY great game!
some suggestions:
add new aliens type, like dog aliens, aliens tanks and ''cars'' alien bunkers, bases and fortress, after all, thet are intelligent, they must need food, they must sleep and all, their idea is not just kill earth lifeform(i think...) i think they just want resources or a new planet to live/colonize.
add new maps, a world map that you can select the places, for example, in some areas there are humans living well, fighting with aliens in a fever battle inpossible to know who side will win;other areas that are warzone over aliens and humans; other areas that were COMPLETELY smashed by the aliens and now are their colonies.
remember, humans arent so weak to fall like birds to aliens, humans aren't so strong to survive(and destroy/kill) giantics infrantry of aliens and an UFO SAUCER completely alone!
after all, i really liked the game, perhaps a little more and he can be the best game of this genre to NEWGROUNDS, perhaps everything(this game) get 5 stars from everyone(players) if you add some multiplayer or something like an endless mode, 'cause the game can be boring after a time playing the same maps, the same story, the same objecives, the same enemies.
other thing: boot up an alien campaing and divide the human campaing in ''guerrila/rebel'' and ''government'', those can be important, to see diferent visions(what the aliens really want, what the government really want and what the rebels really want.
PS:i'm Brazilian, so there can be grammar errors in this reviews.
PSS:4 stars favorited game and favorited author
see ya!