Assuming it wasn't a metaphor, it would still obviously be ill-posed though, right?

It may be that one game can be beaten by someone only on normal, but all levels but one are easier on hard with unlimited ammo. Or that one game is easier on normal and another easier with unlimited ammo on hard. One level might require 72 hours of straight gameplay to beat on hard with unlimited ammo, but such a victory might be reliably achieved, and a 9/10 chance of death each run on normal, with success determined by the third minute.

The metaphor is that people have different advantages and disadvantages. The one person whose challenge is difficulty conserving grenades and separating enemies to confront as few at a time as possible might have little in common with the person whose challenge is grouping enemies such that the fastest and slowest are each hit by as many of his individual grenade throws as possible.