Sybubblun is a hidden game in the port of Bubble Bobble for Sharp X68000. It is an extremely difficult version of Bubble Bobble, featuring graphic elements from the 1988 arcade game Syvalion. It is unlocked by typing "SYBUBBLUN" while holding down the Opt. 1 key, then entering the configuration menu and selecting the newly-added Sybubblun game option. This minigame features 20 levels, which culminate in a boss fight against a sprite edit of Super Drunk made to resemble the boss Glodloid from Syvalion.