The two fish, while they look similar, are different and must be used together in imaginative ways: one fish is bigger and can therefore move heavy objects, while the smaller fish can enter tiny tunnels that are too narrow for its partner. Although your goal in all the game's seventy levels remains the same (to exit each level safely), the 'trick' you have to figure out is always different. Along the way, both fish utter witty remarks about their surroundings, and the various undersea inhabitants quarrel among themselves and comment on your efforts.

One nice feature in Fish Fillets is the non-linear gameplay that opens up after the first few levels. The seventy levels are grouped into eight "paths," which you can choose at different points in the game. This means if you are stumped in one level, you can try to go on some other path. If you enjoy challenging - indeed, maddeningly difficult - puzzle games, check out this interesting and fun puzzle underdog. It's not as addictive or clever as D.R.O.D., but it offers plenty of variety and challenge even for the most expert of puzzle fans. Highly recommended!

Note: Fish Fillets NG / Next Generation is a fan-patched but officially endorsed expansion to Fish Fillets that contains the whole base game and some extra levels along with other enhancements. That's the version you want.