All the challenges...
	Secret Level (EX Stage)...

In CHALLENGE MODE you can fight hidden bosses, visit new stages and and have fun with competent missions. This is the best way to take advantage of Infinos Gaiden once you have completed it.

Unlockable	How to Unlock
BOSS ATTACK	Complete all the previous challenges.
EX STAGE	Unlock and beat the EX STAGE (secret level) during the game.
LEGEND MODE (ALL-STAGE)	Complete the BOSS ATTACK Challenge.
SIN EXTRA STAGE	This is the final challenge and the hardest. Complete the SPECIAL STAGE 3 Challenge.
SPECIAL STAGE 1	Complete the LEGEND MODE (ALL-STAGE) Challenge.
SPECIAL STAGE 2	Complete the SPECIAL STAGE 1 Challenge.
SPECIAL STAGE 3	Complete the SPECIAL STAGE 2 Challenge.
STAGES 1-7	Finish these levels in the game to unlock them.

You need to beat the game at least once in Arcade or Hard mode. Play again the adventure. When you defeat the 6th boss, place your ship in the enemy sphere before he vanishes and a secret warp will appear. Complete this weird level to see the alternate ending and to unlock this EX Stage in Challenge Mode too.