OpenFeint. It seems like a pretty solid platform. Subby currently is just using the shared leaderboard feature, as I haven't come up with good achievements. I was coming up with things like catching some number of the same color fish in a row, but that's about it, nothing too exciting. Of course, one cool one would be for unlocking the shark, still curious if anyone has found it! (Hint: Title Screen)
Also, if you are having issues with Subby controls, try playing with the touch mode. Hit menu and select controls. If that works, try calibrating your accelerometer. Bring up your Android settings and under Display should be an option for G-Sensor calibration. If that still doesn't work, drop us an email.