Bonus hero templates:
To unlock the Astronaut, Knight, Ninja Girl, Spartan, and Supergirl templates, enter the Creation Hall in the Village Map, then while holding L, press X, Y, B, A(2).
Bonus music tracks:
To unlock the three “?????” songs at the bottom of Isaac’s item shop list, collect the hidden Pirate Coin in every level. The songs are “Opening Credits”, Mayor Rosa’s “Light Of My Life”, and the “Real Life” ending song.