Thanks for answering, sounds good!
After playing for a few days (mostly Marathon) I can say I really like it and it plays very smooth. Also the tracks you've selected are great. I have three more (minor) points of feedback:
1. It seems that for Marathon, a random track (from the selected tracks) is played in a loop. I think it would be cool if the selected tracks were shuffled since I'd like to hear different tracks during a longer session.
2. I'm getting accidental hard drops on high speeds regularly when wanting to move sideways. This probably has to do with my wonky GBA D-Pad, but I read someone else mention disabling diagonal press so maybe that option would fix it.
3. I can't say I fully understand "Training" mode yet. I guess it's for practicing optimal button presses? In that case, shouldn't the finesse counter increase for every "unnecessary" button press? Because when I rotate a piece 5 times before dropping the finesse counter still only increases by one.