Did you ever play Donkey Kong Country? If not, go correct that now. If so, you'll no doubt remember that game's fondness for barrels that acted as cannons. Donkey or Diddy would jump into a barrel and then you would press jump to fire them in whichever direction it pointed. Sometimes the barrels moved up and down, or side to side. Sometimes they rotated, and progress from barrel to barrel often meant dodging through bouncing crocs or buzzing bees. Success was all about timing.
Cannon Cat is basically those bits, except you're a cat.
It's better than it sounds. (And it actually sounds very nice anyway, thanks to a memorable backing tune that's reminiscent of Sonic the Hedgehog and other 16-bit platform ditties.) Cannon Cat leaps into a barrel and you tap the screen when you want to fire him in the direction of the next one. The barrels spin and rotate and there are flying ducks to avoid. Later on there are turtles to use as bounce pads (the belly side is your friend, the hard shell is not). After you pass through enough barrels you reach a glowing circular portal, and once you've fired Cannon Cat into that it's the end of the level.