I've done some rudimentary testing. There's a big room in q2dm1 where the frame rate dips down quite a bit when you're just staring at a static scene.

Very interesting:
400x240 hovers around 15 fps
480x288 flickers between 10 and 12 fps
560x336 hovers around 9-10 fps

I was surprised by the small fps difference between the two higher resolutions, especially compared to the big difference between 400 and 480.

I've also mapped a few keys on my BT keyboard, but I'm finding it difficult to play with the keyboard and touch screen. It just seems really awkward to squiggle around on the screen to look, then use the keyboard to do everything else. I'm going to have to continue to experiment... I don't want to change basic key mappings in such a way that I break the keyboardless behaviours...