This is amazing and really fun! This doesn't feel like a gamejam, it really is impressive how polished and well thought out everything is. I read your postmortem and it makes it even more impressive. The only downside is that it's not really a game :) but that doesn't make it less fun. I think the mechanic can be adapted to a more puzzle like approach. If there was one thing I would have like is a few more crazy shapes with longer and more annoying to handle "forbidden shapes", if you know what i mean? Most of the shapes are very "blocky". Amazing job!