Ohhhhhhh snap!
Listing the Gundemonium games as new releases is a bit misleading. They've been available on PC from the start; this week is just the Steam release of the collection.
Meanwhile, elsewhere in the land of rereleases, I'll probably end up getting Civilization V: Game of the Year Edition once it's cheap on a Steam sale.
The Binding of Isaac is supposed to be something like Smash TV meets Rogue, and is by half of Team Meat. I definitely need to play it.
Solatorobo is supposed to be pretty good, but I haven't played it to know if it is or not.