Sparkster is a different game from the Sega Genesis version despite having the same title in North America and Europe, which bore the full title of Sparkster: Rocket Knight Adventures 2, and has no plot continuity with the original Rocket Knight Adventures.
The kingdom of Eginasem, a land inhabited by opossums, is under attack by the Lioness's army of yellow dog and wolf soldiers, which also kidnapped Princess Flora. Sparkster, the Rocket Knight, is out to battle this threat, rescue the princess and save his kingdom from certain destruction. His nemesis, the rival Rocket Knight Axel Gear, is aiding the invading forces, making Sparkster's task even more dangerous. The player's goal is to battle through all of the enemy warriors and robots, defeat Axel Gear and infiltrate the enemy's battleship, where the yellow dogs leader, Generalissimo Lioness, is planning to launch a warhead to destroy planet Eginasem.
The eponymous main character is an opossum knight who fights an army of yellow wolves and robots. He is armed with a sword that can fire energy bolts and a rocket pack that allows him to fly short distances. The gameplay remains mostly the same as in Mega Drive games, with the most notable change being the addition of a short-distance rolling dash. One major difference is that the game's final level depends on the difficulty the player selected. On easy, the game culminates with battle against Axel Gear, but on normal, the story continues with Sparkster fighting the leader of the Wolves on the next level. On hard difficulty, the game continues beyond that, with the true final stage.