Use your left and right arrow keys to move the blob you are controlling and press spacebar to fire it. Your up and down arrow keys rotate the board allowing you to position the blobs all around the grid.
You will have to arrange the blobs on the board in their color groups. If you match the color and pattern shown on the left of the screen the group will be removed and set off a chain reaction.
All other blobs of the same color which are touching the pattern will also be removed scoring bonus points.
NOTE: Reaction can only be purchased via the Mac App Store (the buy link redirects you to its App Store page). To purchase/download applications via the App Store an Apple account is required.
