secret worlds: temple of bryyo
You can access this secret world once you have ship missile. Upon returning, your ship will have to do a bombing run to get rid of the enemies. Head to the middle of the room when they're gone, with the cannon and large storage units. Space jump on the lower storage unit, and again to the higher one. Put the cannon behind you and do a spring-bsj from the back of the storage unit to enter the secret world.