His most recent entry is a classical piano rendition of music from the game's Break The Targets challenge. Before that he took stabs at Corneria, Final Destination, the Fire Emblem stage and Fountain of Dreams from Kirby.
He's been posting his work on the Smash Bros. sub-Reddit where the community's been eating it up. Some have asked him to make an appearance at Smash Con later this month, but he wasn't even aware of it until recently, suggesting he might be able to show up at next year's.
BearKeys says he's never been to a Smash tournament either, although he might attend one of those at some point too. "So far it's just a musical thing," he said in a recent comment. "But one of my students might take me to a Melee match. I plan to main Donkey Kong since there's no bear in the game."
There's not much good sheet music out there for video game music, especially in games less regarded in the sound department like Smash. Fortunately for him, BearKeys has perfect pitch, so instead he gets by with simply listening to the music and doing his best to recreate it from scratch, which by all accounts he seems to be pretty good at. Here he is playing Melee's menu music.
BearKeys appears to draw a lot of inspiration from the YouTube keyboardist Ronald Jenkees, and started his foray into video game music doing covers of some of his stuff, including a version of the ambient water music from Donkey Kong Country. There's something particularly solemn and extra meditative about the track that you can't get except by watching BearKeys perform it decked out in a retro Donkey Kong t-shirt, bleach white fedora, and thick, black rimmed glasses.