How can I trick or force an app to work on an unsupported device?
You can't FORCE it to work. There may be tricks you can play to fake the app into thinking it's on another device, but for the specific app given (video playback), it's almost certainly refusing to playback because it CAN'T.

The hardware on the device is probably something that the devs didn't anticipate, or that the app can tell isn't fast enough to actually work. Even if you find some way to fake it out and make it try, it's only going to crash or play back so slowly that it will be unwatchable.