I love how this game's tile based and has a battle system like an RPG. However, there's really not much substance to this game. It's all just looking around and searching, and that's about it...
Also, the zombies can walk through walls, lol. Are they ghosts or zombies? You need to implement the same collision detection system for your NPCs that the player has. I know you're "AI" is basically a bunch of "follow the player" if statements. (if player is above NPC, then AI moves up, etc) You need to implement the collision detection systems for your levels. I.E. If zombie moves to a certain tile && moves right (to a wall on his right), then zombie position = the tile where the zombie originally was.
Other than that, decent game.