Mostly gratuitous use of 3-D. Should allow for "deselect" so that when moving items you don't accidentally combine. Undo is helpful, but was still awkward at times. Nice idea, though.
Jimmyz...the angle seems VERY fussy and (for me) required a lot of trial and error to get exactly right. Z's advice is about right, but need to hit it spot on and the right distance from the wall.
Adventure games are my favorite genre, but not with artificial tight time limits. The fun is in exploring, not rushing around. An occasional moment of speed for variety is OK, but games like this force boring repetition.