"Tunneling effect" bug: With enough power, cubes can skip through other cubes. Try lvl 14 with 3 bombs directly left to the cube. Doesn't even touch the barrier.
The artwort is pretty good, but reptitive. The differences are all very similiar.
Overall ok, but not nearly as good as "5 Differences" or "6 Differences".
Inferno is just plain unfunny. The puzzles are almost identical and the graphics are, quite frankly, ugly. Maybe good for a couple of levels, but not for 40.