This ability is normally unlocked by completing the third Sparx level, Starfish Reef. This code unlocks a fourth hit point for Spyro, marked by a star-shaped glow around Sparx when he’s gold.
Lastly, you will need to plug in extra controllers for multiplayer, which means 3 and 4 player require a Multi-Tap. Battle Mode lets you play normal matches on all three maps, however you will need to unlock Pogo-a-Gogo in the Adventure Mode to play it here. In Adventure Mode, you can play Pogo Painter, Polar Panic and Pogo-a-Gogo, although the latter is unlocked by collecting the Trophy, Gem and Crystal from the other two games. This code for the PS1 game is entered at the Title Screen.