Heavy Cannon vs Gas Cannon
The Gas Cannon is significantly better than the Heavy Cannon of the First Alien War, and makes a somewhat convincing argument to become the standard armament of all Aquanauts of appropriate strength. With two more shots per clip, less reloads are required; the power of the weapon can make reloads unneeded with efficient use. Accuracy ratings at identical. Snapshots take slightly longer, but the Aimed mode cost is down to compensate. Damage is up across the board, and the weapon can be used effectively anywhere. The fact that Darts and Harpoons are a *significant* downgrade to Pistols and Rifles is also a huge factor. Enemies also have *significant* AP damage resistance in TFTD, making explosive rounds much more relatively effective. The larger maps with plentiful "impact spots" for explosive rounds (various bits of scenery) also make Explosive rounds more effective at killing due to "near misses" than UFO. The fact that the Gas Cannon is the only reliable source of direct fire Explosive rounds above land means that HE Gas Cannon wielders will be invaluable during your early terror missions.