Fun mindless diversion, but needs work.
Nice idea, splattering Teletubby brains all over the place. However, when I played, the timer didn't work, the weapon change transitions were sluggish and the chainsaw was unpredictable.
It would be nice if there was a bonus if you hit a certain amount of TT with the rifle (long shots) or if you got, say 50, consecutive kills without missing. The cows are a cute touch, but I think a -100 is a tad steep for shooting Elsie.
One other thing, I think the enter key would be a better key for ammo, especially if you are using the 10-key pad to change weapons.