Perfect design all around!
I'm so glad Vsauce brought this app to my attention. The premise is simple yet robust, and the typography and color palette are absolutely superb! I don't believe there are any obvious mistakes or glitches, but I'd like to make two suggestions that'd make this game even better. First, I'd like to see a leaderboard implemented so people can compete for the top scores, prolonging their interest in the game. Second, it'd be really cool if there were more triadic palettes that swapped randomly each game. It would look much prettier while also being more challenging, as the player wouldn't be able to memorise the color sequences as easily.