It's very nice to see a game created specially for hardware with a huge number of features. Big kudos on this.
I was really curious on how you solved the shooting since I also made a shooter that would work best for dual sticks, but is limited to a single d-pad. I solved this issue by disabling movement and having the d-pad now free to shoot in any direction. Not sure this would work for a fast paced shooter such as Binding of Isaac though.
Cool game and looking forward to the post jam version. Just be careful with the IP, asking for money when wanting to play could be a legal issue.