Bit.Trip Core is the second game in the Bit.Trip series. It uses the same rhythm-based concept as the first game, but with completely different gameplay. Players control a stationary core in the middle of the screen. The player holds the Wii-remote sideways and uses the four directions on the D-pad to launch a beam and collect all dots that pass, using the 2-button. The beam can only be launched in a single direction at a time, so a quick succession of actions is required. All objects are synced to the game's chiptune music, so the player needs to follow the rhythm to catch the objects in a timely fashion.

By performing combos without missing dots, the game transitions into a Super and a Mega mode, which alters the music and the visuals. When too many dots are missed, the game enters a slower, monochrome mode where collecting a sufficient amount of dots restores the game to the regular mode. When too many dots are missed in the monochrome mode, the game is over. The player also has a bomb to clear all dots on the screen. The game offers three scenarios: Discovery, Exploration, and Control, and they last about fifteen minutes each. Each scenario is split up into smaller sections.

The game can be played cooperatively with a second player.