Hi! I strongly agree with all of your points, the game is literally screaming for some good retouches. I actually had the impression I've already made the pieces spawn in center, but guess that happened just in my imagination (the jam period was quite overwhelming for me in terms of things to do haha 😂).
Thanks a lot for your insightful feedback! And stay tuned for further improvements!
(Later edit: I re-read the code and can tell you that the pieces are intended to spawn in center starting with Level 4. This was an intended feature to give the silent impression of a "work in progress" game.)