Challenge run

[Kura]

Sounds interesting, though I would probably call it something related to the Nord theme, maybe Valhalla or something of the likes.
You can try to limit the overall time of course, but I'd find it much more interesting to put a time limit on each individual wave and remove preparation tome altogether; eg. you play wave 1 with 5 minutes of time, once this runs out, wave 2 spawns - regardless of whether 1 is fibished. This would put a lot of emphasis on players to act or be punished for being too slow.

Thanks Noname for providing a suggestion on this.

The time limit per wave may seem a little better as well as the punishing mechanic, i still think maybe 10 second prep time should be available at least for boss waves or maybe 2-3 waves in total just so the group has some sort of time for preparation.