There should be a button that takes you to the game of the day. That would make my life so much more fun. haha. I click my kongreagate book mark and it brings me here. :)
An easy way to get money is to play lvl 1 of the animal lair and just stick your weapon in the middle of the path. Some animals will get past you but then you will catch them on the way back. :P Just do this until your happy with the amount of money won and then destroy the lair
P.S. I did this with the bat. I am not sure any weapon below it is strong enough to make this work.
The flame thrower is great for lvl 12 because the baby zombies die really quickly. and the sniper rifle is great for lvls with lots of big zombies because it kill them with one shot to the head.
There are a lot of things you should consider fixing. like that statistics during the game. It would be great to see your speed and all that while playing. :P other than that i believe this game is kinds addicting.
This game is fun and all but there is not room for mistakes during the time trial. its a pain in the butt. if there wasn't 33 pu points with I would have given up.