Now here's a hard game to pigeonhole. Squareball, from Swedish developer Drömsynt takes the classic style and mechanics of Pong, then takes that famous white dot on something of a platform-based adventure. That said, the levels also make me think of a very crude R-Type, so maybe it's a bit of a shooter, too.
Anyway, in Squareball the eponymous dot bounces up and down on the walls of the level exactly as you'd expect it to do in Pong. Using the touchscreen, you actually move the wonderfully retro-styled environment around, placing the ball in position to knock the destructible aspects of the levels away.
So, actually, there's also a bit of a Breakout vibe in there as well (although Breakout's essentially single player Pong anyway). The whole thing is very Atari 2600.
It's easier to just take a look at the gameplay video below. It's ultra-simplistic, but I think that's what I like about Squareball. It's going through Apple's approval mangle right now, so we'll let you know when it's out.