Castlevania: Rondo of Blood is designed to be compatible with a Version 3.0 System Card (distinguished by the Super CD-ROM² branding instead of the CD-ROM² brand found in earlier versions). Despite this, if the player inserts a Version 1.0 or Version 2.0 System Card before bootup, the game will enter Akumajyo Dracula Peke, a hidden self-parody minigame. The title logo is deliberately misspelled (i.e. "Akumajyo" instead of "Akumajou") and written almost entirely in hirigana save for the "X" at the end, which sports furigana reading "ペケ" ("peke"); the latter is a Kansai dialect term for a wrong answer or prohibited action, riffing on the fact that the player inserted the wrong type of System Card. Upon pressing the Run button, the game will then load up "Stage X", featuring a much more cartoonish art style and a splash screen claiming that "The fated bloodline will fail without a Super CD-ROM²." Reaching the end of this stage results in Maria apologizing before text appears instructing the player to turn the game off and swap out the System Card for a Version 3.0 one.

Akumajyo Dracula Peke is retained in both Castlevania: The Dracula X Chronicles and Castlevania Requiem, complete with an English translation. However, the ending text is changed to accommodate the different methods used to unlock it in each re-release. In The Dracula X Chronicles (where it is unlocked by beating Boss Rush Normal three times, the third while having the Key sub-weapon during the Lesser Vampire fight), the text reads "Press START button to quit this game." Meanwhile, in Castlevania Requiem (where it is unlocked by inputting the Konami Code while highlighting "Options" in the main menu), it reads "Castlevania Requiem does not support extra lives codes. Press Options to quit, cheater." Both re-releases additionally rewrite the splash screen at the start of the level to say "Destiny cannot be stopped here."