Numerous samples and other prototype versions of Castlevania Bloodlines have surfaced over the years, both as actual cartridges and leaks to bulletin board systems (BBS).
The first was Beta Version 0.1, which leaked on July 1st of 2018, having been in the possession of collectors for some time. This beta only had two stages fully implemented, with the rest of the stages remaining unfinished, along with an intro cutscene that differs from that in the final release of the game.
The second was Beta Version 0.5, which has been known about for longer than the previous beta. This was a version evidently provided as a preview to game magazines prior to the game's release and offers several more finished stages than the 0.1 Beta. However, these stages still differ from those in the final release in that they have several areas that did not make it into the final game, such as a zeppelin and molten steel areas in Stage 4. Many of the sprites used in the 0.1 beta carried over into the 0.5 beta, as well as several sprites from newly added stages, such as the Princess of Moths boss in Stage 5, would later be scrapped for the final game's build. Other smaller sprite differences that were changed to the final release include Eric carrying his spear over his shoulder while walking, Medusa Heads heaving blood on their neck stumps, and zombies having flies buzzing around them.
A hard copy of this beta was obtained by user "TARA200" and put up for auction on eBay in 2002, resulting in some images of the demo with their name plastered upon it for the auction page and were circulating the internet for some time after.
On August 12, 2021, a ROM of the 0.5 beta was shared by user "pulse_project" on SegaSaturno.com. The user "Lord Gambit" was able to take the buggy prototype and make a "fixed" version playable to the public.
The 0.5 beta build features 4 stages that can be played through normally, although stage 4 ends at the molten foundry section and the Konami Code is needed to access the rest of the stage. Stage 5 also exists in this beta, but can only be accessed via the Konami Code and has sections that cannot be advanced through normally. A Dracula test fight can also be accessed with the Konami Code.
Just prior to Castlevania: The New Generation's release in 1993, a European beta was found to be in existence. While largely finalized, it had a few minor differences between it and the commercial game, including enemy sprite attacks being different and environmental tweaks.