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
Biggest exploint? Nah…
Most cool one? Definetly.
Game: Commander Keen 4: Secret of the Oracle From 1991.
I discovered a secret area in the first level that gave you 8 extra lifes. Just take them. Die and rinse and repeat.
Note: I was at most 6-7 years old when discovered this myself and i rebought commander keen a few years ago, the secret area is still there!
edit: here’s a video of the area https://www.youtube.com/watch?v=Z29jQvVLaXY. Still blows my mind i discovered this on accident as a kid.