Passwords
Select any level - enter as password BCKDR
Extra Tank Bucks - enter as a password - DPPCKTS
Unlock all tanks - enter as password THRTN
Unlock all weapons - enter as password SRTHMB
New Gang: Brandon -enter as password SMSLGNG
New Gang: Cassandra - enter as passwoard NSTYGRL
Tips/Hints
And long walks on the wide open fields
Try and avoid levels that aren't in the wide open areas, otherwise you'll probably get stuck and blown by the wayside.
I like 'em big
Use the big heavily armed tanks and just grab power ups to blow away as many enemies as possible. Smaller tanks don't offer any better steering, and you might as well use tanks with more armor.
Fire Soon as you see the pixels on the screen
Don't bother saving your special weapons since your tanks won't last long. MIght as well use what you can.