disk images work fine in emulator but not on real IIgs?

hello everybody!

i just got a IIgs and am really excited about it. i made my own minidin8->db9 cable and have already transferred some images to 5.25" and played them. some images work fine but others (that work fine in the OSXII emulator i have) won't boot. after i've transferred the disk image onto the floppy i boot up and get the bracket command prompt and maybe a few lines of characters (sort of like when the IIgs screen is a terminal for the serial port). other images like Oregon Trail that work fine on the emulator boot up okay on the IIgs but then just stops halfway through.

has anybody experienced this sort of things where a disk image that will play in an emulator fails on a real machine? any insight into why this happens or if it can be fixed/worked around?

cheers,
chris