This is an idea for world war:
World elements: Mines: They act like tombs, except if a zombie steps on one, it will blow up dealing an instant kill of damage to both plants and zombies in that tile. Note: Grave Busters work on them.
Gatling: Shoots four peas like in PvZ1.
Bamboo: Shoots bamboo shells in a 5x5 range, which does 5 NDS with a splash of 1.5 NDS in a 2x2 radie.
PF: Kinda like GW , drops 5 bamboo sticks on each zombie which deals 3 NDS each.
Pumpkin: You know, like PvZ1.
PF: It triggers the plant food of the plant in it. So, if you have an alone pumpkin, it does nothing except it heals it and makes it invulnerable like always.
PF: A leaf shield will appear in front of it. Works like infi-nut PF, except only in three lanes, but it has double the health.
Cactus: Now shoots half as slow as a pea , but does three NDS.
PF: It will shoot a laser-spike-beam thingy which starts out with 200 NDS, but decreases for each zombie it kills. Example:First it hits a normal zombie which will die, and the laser will continue. but because the zombie had 10 health, 10 NDS is taken off the laser! So the laser will do 190 NDS to the next zombie. If a zombie survives the hit, the laser will stop.
Gunner: Stops each tile to shoot the plants. It shoots five shots per clip, and each shot deals a half bite of damage.
Health: 10 Speed: Hungry
General: Kinda like the king , except it commands them to go faster. It only commands soldiers, and he makes them speedy. It moves, too.
Health: 25 Speed: Stiff
Medic: Will heal zombies by half of their original health. Never heals a zombie twice.
Health: 20 Speed: Hungry
Health: 75 Speed: Creeper
Plane: Will fly into the lawn at an insane speed and drop parachuting zombies. Like the announcer, it can't be killed. Before it comes, you can hear a jet motor starting.
Parachuting zombies: They are just soldiers droppin' from the sky. They fall as fast as a bug bot.
Surprise attack: Artillery! Soldiers, Gunners and Medics are shot out onto the lawn.
Zomboss: A helicopter (cant think of a good name!) Instead of spawning zombies, it shoots them out wit a gun. Instead of charging /breathing fire , it leans forward so the rotor slices the plants. Special: Throws out mines at random spots.