Each faction has special ability buildings

[Vokzole]

One of the things I'd like to suggest is that factions should have their own special ability buildings in the game. For example would be the Combine headcrab canister launcher which is already in the game. The Rebel Faction might have a building which can launch artillery strikes while the Antlion faction can have a special Hive building that can deploy a swarm of Antlions anywhere on the map.

To further increase the power of the buildings, there will be upgrades for them. Example, AP Shells Upgrade increases damage for Artillery Strikes. Fortified Canister Upgrade increases life of the headcrab canister. More Antlions Upgrade will create more Antlions at target location.

I think adding a Super Weapon for each faction would be awesome too but that might make the game become too unbalanced.