Is it possible to make a build for Mac OS 10.5 Leopard PowerPC?

So I built an arcade cabinet, and in order to make a more permanent installation of the games my partner and I built for it, I was hoping to throw my old Mac Mini inside of it. The games we made are in Unity 2D, Unity 4.6. The Mac Mini has 1 GB of RAM, but it's an old PowerPC G4. I tried doing some builds of x86 and Universal for Mac, and they appear as apps with the "No" sign through the icon. Is there any way to do a build of our games for this ancient Mac? Or a way to edit the .app files to make them compatible? (I can't upgrade this Mini to Snow Leopard.)