If you want to see trippy stuff, check out
Cyriak's channel.
On topic: the only I can think of to help is to ask if your friend can play other games without this problem. If other games do this, then it's most likely a graphics card problem. It will probably get worse, with the OS looking like that too, and even text mode while you're booting up getting corrupted. Then, it will stop booting at all. I have unfortunately been there. A new card is the only cure, but you might as well take this as an opportunity/excuse to upgrade to a better card.