I’ve built a version of JA2 (Stracciatella) with the 800×600 mod from Mythrell, initial thread here. It is statically linked to libSDL so you shouldn’t have to have any libraries installed and of course it should work on i386/x86_64.
It goes without saying you’ll need the data files to play. Why not buy it here from gog.com.
With thanks to monkey physics for the original package I downloaded which led to the idea of a static/universal version. I’ve not yet got PPC working according to tests done with the arch command but I don’t have a PPC based mac to truly test. If someone can test give me a shout or if you know how to compile JA2 for PPC so that it works please let me know. I’d like this to be as easy to use as possible and supporting all mac architectures is the biggest thing.