The visuals were amazing, and the controls were smooth. Great job on the blood particle effects!
However, I felt like that there wasn't a clear goal nor was it very challenging. I agree with @Chykary that info about what you have to do upon beginning the game would be beneficial. I would also recommend adding things to make it more challenging, such as flying enemies, and as well something that motivates the player to risk her life to get more blood, like filling up a meter to get extra bonuses.
All in all, great stuff, especially for one week! Keep it up!