bjj hero said:
Fiction will always lead technology. You need to imagine it before you can make it happen.
I think this might have been the case up until around the turn of the 20th century, but in the day and age of videogames, most of what you see in them has been proposed to some degree already either to the military or within it. There's very little the US military hasn't tried.
Before 1980, the US military alone had already experimented or explored directed energy weapons (including lasers and concentrated sound), armed remotely controlled aircraft, hyper-velocity projectiles (including exploring the railgun concept, which is generally limited by the need for immense power rather than anything else), a liquid land mine capable of being sprayed on the ground or from the air, the use of the A-12/SR-71 airframe as a bomber capable of dropping a solid projectile to create a localized earthquake, a constellation of satellites that could redirect sunlight to any spot of the globe to illuminate battlefields at night, nuclear powered aircraft, a camouflage system that could be sprayed from the air over vehicles and troop emplacements, weather modification (including hurricane and tornado seeding), disorienting hallucinogens, trained sea mammals (still in use)...I mean the list goes on and on.
During the 1970s and 1980s, proposals for various orbital weapons (including things like orbital lasers, missile launchers, etc) were made, eventually leading to the "Star Wars" missile defense program.
Space based weapons and weather modification even have international treaties either in effect or being proposed banning their implementation. The Enviornmental Modification (ENMOD) convention dates to 1977. The first treaty demilitarizing space dates to 1967. The Soviets proposed a treaty demilitarizing the moon in 1979. I think at this point, you'd be hard pressed to come up with a weapon or military scenario that hasn't already been thought up by one military or another at some level before.