This is a violinist of Japanese violinist Teppei Okada performing both the theme and sound effects for Super Mario Bros. levels 1-1 and 8-4, and the sound effect for the koopa shell against the stairs 1-up trick in level 3-1. Man, I still remember when my brother and I were playing Super Mario Bros. one time growing up and I managed to convince him one of the pits in a water level was actually a warp zone. Then he died and it was my turn again. Honestly, it's probably still one of the greatest moments of my life. I also used to attack him with my Game Boy like it was a brick and whip him with the connector cord whenever he'd beat me in 2-player linked Tetris.
Keep going for the video.
Thanks to my friend becca b, who agrees Teppei should come over and play the sound effects for Final Fantasy VII for me since I blew my television's speakers out.