After levelling my squad leader to lvl 18, I gained thieving skills +5, my cricket bat of doom was stolen from enraged chimp - the notoriously hard 3rd boss - but a decent loot.
oh yeah - buy lots of chickens on one save - medal for chickens makes the money you make increase. then in your impossible save try to get a breeder early on.
Basic tips:
Sherrif : Hold down space with shotgun - auto reload and fire straight after the reload sound - much easier than firing 8 and reloading one at a time.
On page two of tower- buy lots and lots of chickens - best way to make money.
Before trying impossible badge - unlock all trophies - they give bonus'
Best flash game I've played in ages, if I'm perfectly honest.
iGark - they can all be collected on survival. The difference is you can "bank" - or use it as a mini save. It's really only useful for longer games, as the tower resets (but keeps the floor difficulty) - however the tower stops moving so you can go get a drink or whatever.
the challenge is only unlocked if you have played the game before on another site. Delete your internet cookies and it should start from the beginning without it unlocked.
the last level was the one one I achieved with no skil(infinite throwing of men as jump platforms worked well lol) , but the story is interesting to say the least.