The beta worked equally well from main memory, CF and SD card.
I left it running for about 3/4 of an hour with no pause, before the music got to me.
The button response appeared ok.
Sorry I uninstalled it before I noticed the Frame rate but it was ran quite well (about 20-30 fps, I think).
Can I make a couple of suggestions (even though I'm not really qualified too.) You might want to consider having a button configeration for say L/R handed people or those with a sticky button on their machine.
Some form of level progression e.g. every 5 or 6 levels have a boss of some kind.
How about a save function I dunno about the rest of you but I hate playing games where you always start at level one and just play to see how far you get, I like to have some kinda of level progression going on, that way it keeps me coming back for more.
Other wise it tends to feel like, if you play the first four levels, that's it you've played the whole game.
To have an ajustable sound bar it a great plus, so the sound can be adjusted to your environment e.g. playing on the tube, train etc.
It's just that I've only just finished reviewing a game similar to this, while it had some good ideas (nothing original though), the execution and lack of forethought for the end user really sucked.

I don't know if this a monumental project for you e.g. your first one. but there are alot of similar playing/looking games around. either the gameplay, sound or graphic need to be outstanding if really want it to flourish.
Other than that good work so far.