I never did much gaming on my A3000, but on my A4000 I had to use a program called "Degrader" to make it look like a 1.3 OS A500, which is what many of the early games were written for. Not sure where you are located but most of the ADF games floating around are PAL (even if a NTSC version was produced), so if your in North America you may need to boot into PAL as well (Degrader also).
