Interesting story behind this one...

I never played many tower defense games, but one day I bought myself a cheap copy of Defense Grid: The Awakening, and I fell in love.
After mastering that, I saw a good sale on Sol Survivor, and noticed that it had a Co-op mode! I thought to myself, "Different characters with different tower choices and styles of play? Co-op multiplayer? Sounds like a recipe for TEAMWORK! Different specialties for different player characters means COOPERATION!" so then I bought the four-pack.

And then I realized that I have no friends. BUT THAT'S OKAY, SOMEBODY CAN STILL BENEFIT FROM THIS! Good luck to all! (Don't tell the others, but I'm secretly hoping that YOU, WHO'S READING THIS RIGHT NOW, will win!)