Most of the titles work great, but there are some that are wonky. The original Ghostbusters game didn't seem the best emulated, for example. There's also a zapper game in there, which I don't know how that's supposed to be played.
In addition, the built in emulator on the cartridge does NOT like constant game switching. I had the cartridge seize up multiple times while trying to test a bunch of games. Granted, that shouldn't be a problem for regular use, but I ran into it lot while putting the cartridge through its paces.
All of that said, for the most part it's a great cartridge. The key titles -aka . . . the ones you really want- seem to all work great. The Mega Mans, Zeldas, Castlevanias, etc. all work great for the time I put into each one. It'll be great to have all of those titles on hand whenever I'm out and about. The only sad part will be when the battery backup eventually fails, assuming the cartridge is using that to preserve save data . . . although I don't know why it would, given that GBA cartridges -I thought- were already past the point of needing that. Regardless, slightly disappointed to see a battery attached to the board.
All-in-all, it's a solid 4/5. I'd certainly recommend people pick it up if they've got an old SP or something they want to play some of the classics on. It'll certainly end up being a cart that spends a lot of time in my GBA.
