Castlevania: The Adventure had tons of giant eyeballs, which were more of a nuisance than a threat. Without a whip upgrade Christopher Belmont had to kneel down to hit them or jump over them. The eyeballs never tried to attack, they just spawned endlessly and casually rolled on the screen.
Castlevania: The Adventure ReBirth wouldn’t be a remake of Castlevania: The Adventure without them and it looks like there are even more eyeballs than before. Other changes include new enemies, arranged background music, and sub-weapons.
The game is out today in Japan for 1,000 Wii Points and is scheduled for a US release soon.