The version published by eigoMANGA on Steam is a localized PC port that includes bug fixes and various paid DLC expansions.
The Steam version offers several DLCs that add characters, story modes, and technical features: Vanguard Princess Free Download (v1.8.7 & ALL DLC)
Searching for " Vanguard Princess Free Download (v1.8.7 & ALL DLC)" often leads to unofficial third-party sites, but you can access the game's core content legitimately for free or through affordable official updates. was originally released as a freeware doujin title by developer Tomoaki Sugeno in 2009. Legitimate Free & Paid Options The version published by eigoMANGA on Steam is
Adds the final boss as a playable character in Arcade and Two-Player modes. Vanguard Princess Free Download (v1.8.7 & ALL DLC)