He could of been playing on a controller in the second slot...I can tell that he was getting owned because the Asteroth character cursor wasn't moving.
Meh that wasn't ever that hard
For hard bossies try Snk Battle Colosseum
Fireballs unavoidable fireballs
Then whene you get close they stop all your attacks with more bloody fireballs
I think it was a legit 2 player battle. However it only showed the last 2 fights and he could have played nobody for the first 69. The 2P cursor didn't move, but it did change forms or costumes or whatever it was. I don't think he could have made it look that good by controlling both fighters on his own.
In the synopsis he brags about being untouched for 71 fights when it clearly shows that he gets hit.