Vanguard Princess is a one of the highest quality doujin freegame. It's developed by Tomoaki , who said to be an EX-Capcom staff. Vanguard Princess created with Enterbrains 2D Fighter Maker engine or more precisely, FM2K. The game possesses incredible 2D artwork and animations that rival commercially released fighters and it has a nicely composed soundtrack as well.
System requirements
Windows 2000/XP/Vista (with DirectX 7.0),
Pentium III 400MHz, 128MB RAM,
graphics card with 32MB video RAM, 400MB hard disk space,
4-button game controller (1-4 devices, optional).