Thanks a lot!
Well, it's partly part of the original design, and partly not :p I wanted to provide some "3d illusions" and have some mystery as to what's in the level and where, but currently there is too much of that "mystery" and I agree that it's sometimes hard to tell what's going on. I've been thinking a lot about possible solutions, so I'll surely be fixing that, just didn't have time to do so before the jam deadline!
An undo system is also a very good idea.
In case you want to know: there are currently 13 levels, but I plan on turning this game into a full feature project, in which case it will probably end up having like 20-30 levels :)
Thanks again for the kind words and the great feedback!