Ryuku was interesting. I would recommend an option to invert the AD directional controls. There was also a point where the tutorial text was perpetually stuck on the screen. Combine that with the additional snake thing ghosting your every move and the gameplay was a little confusing for me. I did lose at 79% so I will never know the fate of Ryuku, unfortunately.
I think a nice addition would be to allow Ryuku to eat the enemies if they get in the way, rather than just glide through them. Either way, not bad for two days.