Yeah, it's essentially a mod like Capture the Flag and Team Fortress. It just happens to be a commercial product rather than a freeware one. It'll work in RTG mode, of course. It'll work in any screen resolution you can run Quake in. Most (all?) of the Amiga Quake ports over the years are RTG-friendly. It just so happens that a 68k chip just isn't powerful enough to make Quake enjoyable, in my opinion.
If you end up getting it, you can always use it on your PC/Mac/Linux box (with Quake installed) if you find the Amiga too slow.