I'm a big time Tetris player, and a bit of a snob about gameplay. This is an absolutely wonderful breath of fresh air. Originality in Tetris clones is hard to come by, but this game's gimmick is just so, so good. Switching between modes feels seamless, the game screen is really clear, and the roguelike aspects just add even more awesomeness. I cannot wait to see what the full game has in store!
I have two nitpicks about the Tetris.
Firstly, the Tetris tuning (left/right piece movement timings) In defense of the creators, getting Tetris gameplay mechanics right is actually surprisingly difficult. Personally, I would increase the startup time for automatic piece movement. Right now, It's a bit low, which means a slightly long tap intended to move the active piece one tile over may activate automatic movement and spill it into an extra column over. This detracts slightly from the gameplay when you mistakenly place a block where you don't want.
Secondly, the rotation system seems limited, and I can't tell what was used. Allowing some more complex spin moves to fill in holes in the stack creatively would raise the skill ceiling for Tetris gameplay. I don't count the rotation system design against the game as is though, because it feels fine for all basic Tetris stacking, and also, designing a rotation system from scratch is one of the most difficult parts about creating a Tetris clone.
Bravo!! This game rocks so much.
-Kibi Byte