Maybe 8-9 minutes? It's not a very long game.
Thought later on that the boss fight skip could maybe be done on the right side of the screen too. It would save some time...
EDIT: An encode that goes a bit further than the last .vbm I posted:
http://www.youtube.com/watch?v=kJFoANYJg_E
Usually the temporary walls which block exits are so close to the screen edge that Van Helsing can't fit behind them, but in the instance of the skipped mini-boss fight, he can. By jumping on top of the walls high enough, you get past the temporary wall and (on returning) the boss fight disappears. Too bad this doesn't work on the right side of the screen, because it would've saved more time. By the way, I wait a bit before starting the jump or else the fireball will hit Helsing. Also, the grappling hook in the middle of the conversation is to do a glitch which starts the fight early - normally the characters would still chat for some seconds.
Boss Marishka is pretty interesting here too. I manipulate luck to deal high enough damage to her, and only hit her right as she teleports, preventing her from going in her 'takes damage'-animation which lasts over 25 frames.