Despite (or because of) his quirks, EB is very good at Mario. He got a Star in Tick Tock Clock by stopping time...and the clock has to run for you to get it normally.
He beat Koopa the Quick's second race in under 22 seconds.
The reason the last Mario episode was so delayed was because, due to a computer error, he had to get all 119 Stars again. And he did. (You can see on the file select screen that on file B, he has 120 stars--he essentially played the game twice for the sake of continuity.)
The entire final episode. Due to Bowser's mind control, he loses all his lives right before going into the final battle. He proceeds to hand Bowser his ass. Immediately following the fight, however, he purposefully leaps off the stage so that he can do one last TELEPOR for old time's sake. Which implies that e he fought Bowser twice with no lives and minimal health twice, just for the hell of it. As he said in a previous video, he never uses stave sates.