Magicka

I got it a few hours ago. It's a lot of fun, although having to redo a level all the way from the start if you close the game / go play multiplayer sucks. Steam + Lightning + Arcane beam is pretty much the best combination right now (Q F A S (optional 3 more A or S) > hold right mouse button and watch everything die). The fact that you can add just about any spell to your melee weapon makes things a lot cooler too: steam + fire + earth + shield creates a line of volcanoes, while just using earth + shield would create a line of rocks. The amount of combinations is insane, and that's even without counting the "Magicks". Some parts are really hard though, even if you use the strongest combinations of attacks, mainly because lots of things can just kill you in 1 hit (or 2 if you use shields). About the most fun you can get out of $10 really. Meteor Shower in multiplayer is fun, as is crossing multiple beam attacks(yay for friendly fire?).