Quote Originally Posted by Tanooki View Post
Tarzan for GBC isn't happy with the GBA either, don't remember the specifics as I haven't owned it in like a decade.
It's a sound problem. I just found an interesting list of problem games here:

Densha de Go
Densha de Go 2
Hamster Paradise 3
Hamster Paradise 2
Disney's Tarzan
Sakura Taisen GB
Koro Koro Kirby
Doreamon - Study Fighter 99 Games
Japanese Chess
Battle Athletic
Game of Go
World Soccer GB2
Tokimeki Memorial Pocket: Chapter of Culture
Tokimeki Memorial Pocket: Chapter of Sports

And they note:

"The gameplay on the games is unaffected and there have been no graphical faults found. The problem lies in sound compatibility. The GBA’s new sound processor just will not run some of these games and no one knows why."

However I can vouch for the incompleteness of that list, as Veediots and Top Rank Tennis definitely have sound issues, and folks have already mentioned the audio issue in Rampart and the crashing problem with Road Rash.