Okay i vote for ocean battles and underwater battles
choices:
LAND(MEH)

AIR(MEH...BETTER)

OCEAN(...I WANTS IT BADS)

UNDERWATER(DON'T DENY IT YOU WANT IT BAD)

UNDERGROUND(EPIC)

SPACE(LAUGH, CRY I DON'T CARE AS LONG AS PRIME'S FACE IS USED AS A DRILL ON THE MOON)

CITY(HUMANS CAN FLY NOW CURTOUSY OF ROCKETS AND LASERS)

TOWN(HICS CAN NOW FLY, SAME AS ABOVE)

INSIDE SPACESHIP(BEYOND EPIC)

ON A BOAT DECK(WHY NOT)

MOUNTAIN(OPTIMUS'S FACE + MOUNT EVEREST + MEGATRON'S FIST, YOU DO THE MATH)

SWAMP(BECAUSE FLYING CROCODILES WOULD BE F'ING AWSOME)

RIVER(NO REASON JUST FOR GIGGLES)

POND(NO REALLY THINK ABOUT IT)