Thunder Spirits is a modified version of Thunder Force III made specifically for the arcades with reworked graphics - although still very close to what the Genesis was able to offer. Thunder Spirits puts you behind the cockpit of a lone starfighter out to destroy all the enemy forces of the Orn empire by clearing 8 enemy-infested stages set in various outer space locations. Most of the game levels are taken directly from the Genesis version with a few minor changes. (mobygames.com)