This is pretty nice, but there's quirks too it.
First is the emulator menu is slow and unresponsive, there's a long irritating delay moving between selecting something on a list. It often freezes up after pressing enough inputs.
The actual menu is very nice looking though, very very nice.
Second is the lack of control configuration. I'd be much more comfortable using something such as A/X or X/B to input the Gameboy's A and B buttons.
A/Y should definitely NOT be the default in-game.
Thirdly is you can't change the clock speed, which WILL be supported in the updated caanoo firmware on Sept 15th (I have an advance update)
Although since this is only gameboy emulation is doesn't hurt much.
Finally, I don't know if it's just me needing to adjust to the caanoo or not, but it's difficult to play tetris on this emulator, when I press down I often find the tetromino shifting right instead. I think the directional input may need adjustments, like deadzones and diagonal tightness.
The diagonals are WAAAAY too loose on this, I push all the way down on the analogue stick, but a *slight* shift to the left or right makes it input a diagonal.
There's a total lack of dead zone, the slightest nudge of the analogue stick registers an input and that's not good. You should have a deadzone of about 50%
I'm loving the upscaler on the caanoo screen, it's beautiful, Scale3X+Sample .75x looks gorgeous.
I expect a few flaws like these on a quick release though, but this is a fine emulator! I hope you can fix these.