@botdffreak Have it jump twice towards you, and then have it jump over you. shoot it in the butt. Then get close enough that it can jump BACK over you, and shoot it again. The third time YOU have to jump over IT, so time it well. Good luck!
If you want to win all you have to do is... Save people right at the very beginning. It gives TONS of EXP and is simple. Buy the Magnum, but don't upgrade it. Save all the people and then you should by the flamethrower. Then just kill zombies every turn until you go down to 30 health (you heal 20 every day). Slowly max out the flamethrower and then do whatever.