You can download and check out the demo of the game here:
http://outofmymindgames.itch.io/zombification
Keep in mind that this is like an alpha version, so not everything is working. For example saving :] when your dead your dead and you need to start over :] also to exit game use alt-f4 :D, besides these inconveniences game should work just fine.
Last level is in sewers and there are 2 bosses, so once your done with them this is the end of demo.