Putting out an idea and waiting for it to be ripped to shreds!
Anyway, here it is:
An item for the human team, the demolition charge is a remote detonated explosive, carried on the user's back (so it can't be used with a battery pack, jetpack or battlesuit). When bought, you are given 2 items, the explosive and the detonator. Although you may only carry one explosive at once, you can use the detonator to set off any charge, by aiming at it and pressing the "use item" button with the detonator selected. The explosive is heavy, and to compensate for it's large damage and explosion radius, could possibly slow the user down, or reduce stamina or some how inhibit mobility. Also, it cannot be thrown, but rather is placed at the user's feet. Although they are remotely detonated, you must have a line of sight and be able to target it to set it off.
Anyway, that's my idea, comment as you wish.