God this is so well done.
I found the minigame fairly unforgiving -- I'm not sure if this was because I was getting a tiny bit of lag from wireless controller / playing in a browser or a skill issue (NARRATOR: it's definitely a skill issue). Even so I love this so much and your team should be super proud. I will say managing to nail an inspired piece is super rewarding.
Art and music are perfect for this and even the plodding speed of Bert which I normally would hate in this style game fits the story so well that I'm in love. Only critical feedback I've got is that I found the targeting along the bottom row to be finicky -- i suspect because Bert only has a left/right facing -- and the timing is maybe a bit tight leading to a high skill floor.
All around bang up job folks.