This was actually pretty dang neat! Impressive work in the given time! I sat there every level and was like "WAIT THERE IS ANOTHER ONE?"; Took me a moment to realize that the ceiling is also in play but I got there eventually. The player being able to interact with the laser really added a very nice element though without a tutorial during the first level I thought "red laser= bad, should not walk through it".
If you want to flesh out this demo further I think for some quality of life putting the blocks on perhaps the wall or a lower table (maybe an inventory type setting where one can scroll through the available picked up blocks) so one can see what connections can be made with which block would be neat.