Unreal Tournament 3

From the main menu set up a Deathmatch multiplayer match on the "Fearless" map.

You could get this more easily with another controller as you don't have to be worried about getting attacked.

Find the Invulnerability power up on the map and wait for it to spawn stand where it spawns and then do other things until you get it.

This powerup is located on top of the statue in the main room, accessed by a lift behind the statue.

It takes super powerups around 90 seconds to respawn. So set the match time 30 - 45 mins.

This achievement only requires 10 mins instead of 20 like the others.

There is only one map in the game that contains this Power-Up, and that's the Fearless Map in Deathmatch/Team Deathmatch.

The quickest strategy into getting achievement is to just place yourself "only" in the match, and using the Speed Freak Mod to increase the time. This can be accessed in the Mutators Sub-Menu. Set the match for a full 60 minutes and then once you're in the map, head to the area where the Invulnerability spawns. It's on a high platform nearby two lifts, where some Health Vials are and the Link Gun. When it appears, grab it and step back and idle until it re-appears.

Because you're using the Speed Freak Mod, it dramatically countdowns the power-up faster, but still makes it count as if you held it for 30 seconds or more.

Rinse and repeat this process, and you should have the achievement unlocked before the time runs out in the match. It is possible to go into overtime, since you'll be the only player but I don't think it is needed.