I would really like to see you reimagine or remake this at some point. I basically agree with the problems brought up by teacherpeter like the random spawning and limited gameplay (in my opinion, the music fit the theme and sounds good). However, the movement and concept feel good so I could definitely picture this being something greater like a platformer or side-scroller. You make the jump button give the character more of a boost and the character could make his way to a castle to vanquish the zombie source. You give the player a chance to stop zombies from killing other people. It's just an idea, but it sounds cool and maybe you'd think so too?