Back to the game: It has 30 levels, all of them are brand new. The physics is still as smooth as ever though it can be improved, I think. The difficulty is from easy to moderately challenging. The key to winning a level is to determine the sequence of your actions and time it perfectly depending on the moving objects in a specific level.
ZE may not be the game if you are looking for challenges but its quite good if you just want to relax and, you know, impale some wacky looking zombies dressed is business attire. I was playing this at maxgames website and encountered a glitch on level 11 where both of the icicles got stuck leaving no room for the axe to swing to get momentum and effectively hurl on that target on the left of the screen. But it turned out it was just a browser problem. I restarted the browser and everything went fine. Meanwhile, here is Zombie Exterminator Level Pack walkthrough demonstrating solution for each and every level of the game.