How would this work on stuff from Shadowrun, Blades in the Dark, World of Darkness, etc.? And if not, are there any possible adaptations?
The secret is that you just need a range of numbers to use and lots of obstacles to roll against.
A lot of OSR games tend to have numbers from 3-4 (damage, weak creature HP), 12-15 (AC/DC), and only a few numbers higher than 20 (boss HP, etc). A single dungeon room might have 4 goblins (each with 6 HP), 3 piles of treasure, a fire trap (DC 14), and a dragon (d12+4 damage). All in one area.
But Blades in the dark (and other story games) have scenes that flow from one to another. I don't think Overpowered would be as satisfying to play through unless you laid them out in greater detail (6 guards around the manor, 3 ghosts in the vault, etc etc).
For shadowrun I would use the pool sizes. E.g. if something has a soak of 12 dice, then you need to spend 13 or more Power to overcome them.
If all else fails, then simply assign your own values to things.
Minor obstacle - 4
Average obstacle - 8
Tough obstacle - 12
Major obstacle - 16
I hope that helps!