DAS is 1G, but DAS charge resets on rotation, making it a couple frames slower to move a piece after rotating it.

If left or right is held on the frame a piece spawns, DAS charges instantly.

Soft drop appears to be about 9/8ths rows per frame and causes instant locking upon landing. Note that the piece is still highlighted for a couple frames after locking. There is no hard drop.

The power of the explosion is (number of lines formed simultaneously) + (number of previous hits in the chain reaction). The higher the power, the bigger the explosion, with high powers giving a score bonus:

Explosions are always centered at the bomb.

Putting 4 bombs in a 2x2 square causes them to fuse together into a big bomb, which always explodes in a 10x10 square. However, the game checks for fusions after checking for detonation, so creating a 2x2 square while simultaneously completing either of the lines it occupies won't get you a big bomb before it blows up. If there are multiple possibilities for a 2x2 big bomb (e.g. a 3x2 rectangle of small bombs) then the game fuses the highest 2x2 possible, with ties within the same rows broken in favor of the leftmost square. Creating a big bomb also adds 1 point to your score for the level.

The results screen at the end of each level takes 2 frame per point -- 1 frame per point to tally up your score for the level, then another 1 frame per point to add it to your total score.

The RNG appears to pick up entropy through controller input on every non-lag frame, so extraneous button pushes that do nothing or cause a failed rotation can be used to manipulate luck, as well as holding buttons longer than necessary.