I still find both Geometry Wars games addictive like crack.
Feeding Frenzy 1 has been a guilty pleasure of mine over the last week or so. Anyone enjoy 2? I am thinking of grabbing it.
I bought War World when it first came out because I am a sucker for mech action but I didn't know that a lot of the PC features had been removed, like mech customization. It kind of sucks as an XBLA title.
I really, really enjoyed Castle Crashers when I first bought it, and co-op was a blast, but once I had completed the main game with all the pets & weapons and most of the Achievements, and slogged half-way through Insane difficulty, it just became boring. I would recommend waiting until its price drops, if/when it does.