Awesome! This was lots of fun! The visuals look amazing. You can even see the texture in the players fingernails. Game play is really fun. If that dot is on that pumpkin then it hits. Distance and moving targets are taken into consideration, which is a very nice touch. I also hear some CS sounds when the guns are firing and reloading, nice lol. I only have a few minor issues with it. There is no mute button in the game itself. The only pause button is the escape button (not a bad thing), and there is no way to get back to the main menu without refreshing the browser. In the main menu options there is no full screen screen. I tried alt+enter and nothing. Full screen is something to look into, especially Unity was used. You specified that the rifle was a semi-automatic rifle, but the rifle used in the suburbs was a bolt action rifle that just shot semi-automatic. I got a laugh out of shooting a bolt action over and over with out chambering a new round though. One more thing is that when you sit at the main menu for too long the pumpkin heads dance their way around the screen. The left one will dance itself across the menu and eventually glitch into the screen, while the right one will disappear off the screen. Other than that I think this is a great game! Audio works pretty well with the game and all menu buttons work (I highly suggest you change the link buttons to an external tab/page. Clicking the link and having it go to that page on this page is a bit annoying because then we have to go back and restart loading). Keep it up!
P.s. Found a glitch when writing this. When you hit the escape button while its in the slow-mo mode after hitting something the game will freeze.