The game's flow is a bit confusing to me, because it's clearly taking tetris as inspiration for some things, but it doesn't really play like it at all. It works better as a puzzle game without the pressure of the pieces dropping, so I think a change in perspective could do something for it - perhaps something like having a board where pieces may come from all four sides? With the ability to rotate them, or the ability to switch what side they're on. Something like that.
Other than that I do like the puzzle style gameplay in itself, and the levels do get challenging as they go on. I played for a while, however I hit a level where this type of block would always appear, which would freeze the player controls other than still being able to use the pause menu: 