shared leaderboards? multiple gameplay modes? quick rounds and huge multipliers? some of the best twitch you're going to get.

(Although I *do* love me some Ikaruga.)

I've played lots of R-Type: Final, but mainly to keep just unlocking new ships. It's gameplay is pretty soft compared to most others.
Me and a buddy had a few pretty solid nights getting drunk and playing Gradius V. That game was NOT fucking around.

Those are the two biggest I've played, probably, besides Ikaruga and GW2. I know I've played others, but never binged quite like those.