. Tons of bonus features and frequent payouts keep you coming back for more. The story of. Dive into the vibrant Irish world with Microgaming's Rainbow Burst online slot. The Celtic patterns set the scene of a Great Britain of yesteryear and frame This is a game for the brave and bold! MicroGaming Online Slots. Play Celtic Courage online slot and win a pot of gold. Uncover golden treasures and enjoy the Rainbow Re-spin and Free Spins.