Popping and Entering
Get ready to go bad. Start by shattering both windows of the downtown balloon shop. It's unclear why these windows are vulnerable to sonic attacks, rather than plasma beams, swords, or dynamite, but that's just the way it is.
Go inside and push out the stack of stuff. This creates a platform by the Marvel vent above.
There's a crate here, but it's actually easier to jump up from the nearby snowbank.
Go through the vent and, as the shopkeeper pleads and wails for mercy, smash his stock to get a gold brick. Monster.