On the second test with the boxes and box laser, a couple of issues. The laser is not visible while the wall is up, making it a bit tedious to aim, put on restraint to check, then re-aim the laser. Also, the exit door doesn't visibly open, but you can simply walk through it.
I wasnt even sure the level could be beaten, First I put all the boxes down the chute which softlocked me, then i built a ramp up to the laser but angling it at the blue point only made it light up and nothing else happened, then i brought another box up there and it made the reflector flip out and shoot out of the level XD