It's a really great start of a game. I like that the first part involves just running and evading the enemy without any engaging at all. I was pretty sure I got the green key card, but couldn't get through the green doors. I was able to bash the zombies on the other side of the green doors anyway. It looked like there would be more game to play from there though.
I also really like the music. And even though the running is only two sprites, it works really well.