Since no one has replied I can give some general advice.
DOA2?!? unsure I don't have an ISO, did have the real game its probably the best looking DC games out there. I dundo check youtube see if anyone else is emulating the game.
HL, I swear I tried to run this on an older version of NullDC had had the same problem; its also worth pointing out that Half-life was never released and the version I played felt like a late Alpha or maybe an early Beta, the frame rate diped bellow 20FPS very often, it could also crashed to a debug screen a bit latter in the game, oh and saves take up a hell load of VMU space.

so yeah I don't think this one runs anyway. Oh and it has Updated HD Weapon and Character models and blue shift!
BUT unless your running it on a real dc why bother? your already on a PC so goto
http://store.steampowered.com/ and buy it, Opposing force is also another A+++ games, blue shift is ok.
As for SSF are you on Windows 7? I have had issues with mounting and SSF not even seeing my virtual drive, weird all games run perfectly fine if I burn a CD, so I'd try that next.