Very polished game, really solid experience. I will admit it took me a very long time to realize that you could only use shapes on the top lines, which is obvious in hindsight and it's fair to expect better from jam participants, but... yeah, I'm that dense, haha.
One thing I've noticed is that you can place a shape even when there's a gap left below and there's nothing that would actually support the piece. Is this a bug in the reverse-time matrix?
Continuing with the existential questions, I bet the more tetris-versed attendants will also start debating whether positions like these should be valid and accepted, as they could be "reversed" in many tetris versions. Maybe more modes and options!
The animations for the pieces and in the game in general are also really nice, the details on the main menu are super cool, the sounds are very well chosen. All around, a really tight package.