Working on a High Score for this game? Well here's some tips for racking in the points:
1) Basic Combos - an obvious one, shoot as many guys on the screen at the same time as you can and reload quick enough to continue popping guys on screen
2) Headshots - not 100% on this, but like Time Crisis 2, more points will be awarded for head shots.
3) Item combos - In Crisis Zone, pretty much everything can be shot at, so when you're not popping some bad guys, take a shot as the scenery. Try not to just fill the screen with bullets, concentrate on certain objects in the background, such as barrels or flowerpots, because it requires more items to be broken in order for it to count towards a combo.