Awesome game! Love the implementation of the theme and restriction here. It's a fun and unique gameplay loop that I think works great! Having just beat the game, I think the placement of the barcode is basically random for some of the puzzles since things like the fire/laser/water drip make it nearly impossible to predict where the water is going to be. That being said, I actually found the first water drip area to be the most difficult since the later laser levels the laser would sometimes not hurt the barcode.
Anyway, great game!