Great game till the end...
The music was decent and there were no sound effects but because of the catchy storyline you could really overlook that. Apart from that the level design was good and I liked the art style (it reminds a little bit of Yoshi's Island). As said the story was very good.
Now to my rant: In the final fight (flying around with Derek) the controls seem to lag sometimes completely and sometimes Vlad stops to move for about 5 seconds or more. I know this doesn't have to be a classical programming bug, but it's like saying "you know what player?`I hate you that you've played through the whole game and now I'm gonna frustrate you totally".
So if there's anyway you could improve the player controls I'd be very glad...