This is very simple but so effective.
It's been done before, but I don't think there has been a thread about them here at FP.
Basically, all you do is to take a random game box art, select half of it, flip it horizontally and align it with the original image.
A tip is to mirror the game through the center of someone's head on the cover.
Here's a bunch of flips I did!
TONYY NOT PRO ORP:
Jesus christ it's a flying Tony monster!
Let's play some FARORAF:
Oh, wait, I mean 2YRCCRY2:
Serious sam is serious:
OH FUCK SERIOUS SAM IS BACK WITH POWER:
Now flip some more games! :D