My first OS X game when I bought my iBook, was Otto Matic and even then on the 500Mhz G3, it was rather unplayable due to the weak ATi chipset that was on it and it's 8MB of vram. The iBook itself had shipped with OS X.1.x which didn't do it much favor.
My second iBook I had bought was far better equipped for gaming with the Radeon 9550 but limited to 32MB of vram. Still, the CPU and the rest was far better and it shipped with Nanosaur 2 pre-installed. The 1.5Ghz G4 ran the game amazingly smooth but to really enjoy the game, I needed a gamepad.
Despite the game being rather "odd", it was great to look at and rather impressive looking on the little 12" notebook. I know it's a UB game now and compared to my old PPC Macs of the past, that game should scream at native resolution of an ACD and a fast MBP running it.
I just loved flying around blowing things up.