When I was playing dying light with friend we discovered that every timw you go to sleep and wake up air drop will appear, if you don’t know air drops are pretty rare and if you collext them and deliver to one guy you will recieve lots of xp, we used that multiple times to unlock grapling hook very early. Air drops also gave lots of medicine which was hard to get in early game and that very helped us
In an MMO called Tera, I found if you deleted a certain Terrain file in your games folder and entered a certain endgame dungeon that was easily solo-farmable for expensive leveling materials at the end but really quite long, you could spawn in and immediately fall right into the boss room skipping a 30m loot run.
Not that i did that of course.