Yeah it seems like your rotation system does not have any kicks. Maybe you could make the ceiling a few blocks higher out of sight, so the I-piece would have enough room to rotate.
Otherwise this is a great game with great graphics and I am finding it fun, although there could be more DAS control options and the keybinds don't get saved, at least when I am not logged in.
Adding piece lock delay would help a lot with tucking pieces under others.
An option to turn off the feature that burns lines stored up in the meter on the left is nice. If I try to play clean it can hurt when the stack gets completely burnt and it feels like I stacked upwards for nothing.
Edit: now after about an hour of playing, I can say that the burning feature is really good. If I stack well I can get a few pentrises in before the downstack. If I start making holes it make the stack more manageable again. Great mechanic!
I got a 1,164,000 score just now which is by far my personal best. Playing gets tedious at a certain point.