It's interesting to see the evolution of games from a common starting point. The starting point in question is
Harvest: Massive Encounter, which through its generalized template and addicting gameplay has managed to push forward with an army of similar games.
Creeper World is one of these games. Released not too long ago, it utilizes the basics laid down in
Harvest and changes them to create a game that is very different from
Harvest in many ways.
Creeper World revolves around using your defenses to push back an ever-advancing wall of goo. You do this long enough to activate the rift generators, which then warp your ship out of the area. By using energy collectors, relays, and different kinds of turrets, you gradually make your way across several worlds in search of an escape from the advancing creeper. It's not particularly pretty or amazing, but the gameplay itself is good. You can try out the demo or pick the game up for $20
at the developer's website.