Some sort of upside down bug

[TheFixXxer NL]

Hello people,

I am about buy amnesia and penumbra. I have downloaded the Amnesia demo about an hour ago but there seems to be some sort of bug which makes the demo quite annoying to play. It began to show up in the intro and it became even worse when i could finaly look around. The game is not upside down. But i can see the bloodstains laying on the ground (As it should be). But when i look at the sealing i can see this bloodstains a little bit transparant on the sealing as wel!!! The same goes with The windows are transparant as well which can also be see on the ground. My english isn't my best and i did my best to explain the situation. How can i solve this problem? I really want to give this game a go but with this issue i just can't be botherd to play it and i don't want to take the risk and have this happen to the bought version.

Kind Regards