It's a retro genre influenced by music made on 8-bit systems like the Commodore 64 or Nintendo. Sometimes it is made on those old systems or it's made to sound like it was or it just incorporates that sound into otherwise more modern-sounding music.
If you want an example of old-school 8-bit games music, I loved the music from Bionic Commando when I was a kid
The skating game 720 degrees for the same system had the most intense music I've ever heard in a game, though not in a good way.
Nowadays, groups like Sabrepulse make stuff like this .. can't say I'm impressed. The time signature sounds fairly traditional in this one by the way.
edit :
Wow, Urban beat me to it.