"I just sort of forgot about it for a week," said Firoiu, who coauthored an unreviewed paper with William F. Whitney, the NYU student [who helped him] on the work. "A week later I looked at it and I was just like, 'Oh my gosh.' I tried playing it and I couldn't beat it."
Business Insider points out that their AI read the players positions, velocities, and states directly from the game's memory, so the AI responds six times faster than a human player. To compensate it played as Captain Falcon, the game's slowest character, but there was one crucial glitch. "One particularly clever player found that the simple strategy of crouching at the edge of the stage caused the network to behave very oddly, refusing to attack and eventually KOing itself by falling off the other side of the stage."