From now until 8/16/17 you can download shovel knight for free as a playable character for Blaster Master Zero for Nintendo Switch or 3DS. After 8/16 it will be paid DLC. Link for information only. You will need to access the Nintendo eShop for the DLC. This should offer some good replay value for the game.

http://blastermaster-zero.com/en/product/dlc00.html