The small changes that have been made are that a boss is now encountered every five to ten levels , giving those scenes a similar prominence to Rainbow Islands .
The player takes a branching route through the levels by selecting one of two doors after every boss .
The small changes that have been made are that a boss is now encountered every five to ten levels , giving those scenes a similar prominence to Rainbow Islands , and the player takes a branching route through the levels by selecting one of two doors after every boss .