Revenge of the Titans is a game I've been meaning to talk about in some capacity for a while now, but was never clever enough to come up with decent justification. Thankfully for us, there's now an open beta/demo thingy -- I couldn't ask for a more perfect excuse!
Calling it a tower defense game sells it really short, but I don't entirely know how else to describe this one. Does "worth playing" work for you? Because honestly, that's what it is. Take a good hard look at that screenshot and tell me you don't want to play Revenge of the Titans. I won't believe you.
Pre-ordering the full game early -- as is increasingly becoming the case for these sorts of situations -- significantly drops the price. You can reserve Revenge of the Titans for a mere $13.37 (I see what they did there), which ends up being 50 percent off the release-day-and-onward price.
Revenge Of The Titans: It’s A Demo [Rock, Paper, Shotgun]