The Shock Bomb can be used to stun enemy Defensive Buildings (except Mines, Boom Mines, and Shock Mines) in an area, but if your own troops are in the area when the Shock Bomb lands, then they will be stunned too.
The durations of the Shock Bomb will not stack if multiple bombs are fired at once on the same spot.
Offensive Strategy
Shock Bombs are best used for stopping strong defenses which depends on your troop composition.
When attacking a Hammerman HQ with a Super Mortar, use a Shock Bomb to stop it from seriously damaging your troops.
Using a Shock Bomb and a Flare to deal with key defenses is a good idea, because it makes sure that the shocked defense is taken out as quickly as possible so that it cannot fire upon your troops.
Try not to hit your own troops, especially if you have a high-level Shock Bomb, as they will be stunned for the duration of the Shock Bomb.
In Smokey Zooka attacks on Operations, it is sometimes beneficial to use a Shock Bomb on Pvt. Bullit (or a Scorcher) to allow your Zookas to be placed in a desirable location relative to these high health units. This is most useful when there are a large mass of defenses, especially Rocket Launchers, that cannot all be shocked conventionally without a boatload of Gunboat Energy.
Defensive Strategy
A Shock Bomb is much less effective if it only hits a single structure, so keeping key Defensive Buildings spaced well apart will reduce the threat of Shock Bombs.
It is good to know that if there are seven squares between two Buildings, both of them cannot be shocked with a single Shock Bomb.
Placing Flamethrowers and/or Shock Launchers between the border of the island and the Headquarters is a good idea, because players that attack with Warriors that Flare directly to the HQ (or Outpost) will not be able to shock the Flamethrower or Shock Launcher without shocking his/her Warriors.
Upgrade Differences
There are no visual differences between upgrades. However, the duration of the effect increases by one second each time the Shock Bomb is upgraded.
Trivia
Shock Bombs are very similar to EMPs (ElectroMagnetic Pulses).
The Shock Launcher's munitions are very similar to the Shock Bomb, but unlike the Shock Bomb it can only shock troops even if other defenses are in its area of effect. Also, the Shock Launcher does a small amount of damage to your troops while the Shock Bomb does not do damage to shocked defenses or troops.
The Shock Mine's effect is also similar to the Shock Bomb. It activates when a troop steps on it. This triggers an explosion that does damage and stuns troops for a longer period of time than the Shock Launcher.
