Condensed reviewer mode: on. Act of War: Direct Action. C&C Clone. C&C Beater. Explosions. Techno-thriller. Terrorists! Conspiracy! Actually really good. So-bad-they're-good cut-scenes. Should have sold more. Expansion pack!
As well as the usual selection of new units to fill out and help tweak the balances of the three-sides and a new single-player campaign (which sadly dumps the real-world footage of actors), there are two major additions to Act of War's actual mechanics: Mercenaries and Navy combat. They're so important they probably deserve a paragraph each. Carriage-return time.
Mercenaries are a shared-unit type, available via the same building to all three sides. They're essentially expensive, powerful and fragile fast-response units which you pay a set fee for and then pay a low repeating retainer as long as they're on the battlefield. They've got the second advantage of being able to be dropped anywhere on the battlefield as an instant response thing - the further into enemy terrain, the longer the delay until arrival while a mercenary chopper reconnoitres the terrain (it can be destroyed by the way, preventing you from dropping mercenaries on the enemy base). As well as basic types of combat medics or support troops you can, if you research appropriately, hire illegal mercenaries including the techno-thriller classic of a dirty nuclear device in the back of a truck. Mercenaries work, add a new element to worry about in the game and offer little worth criticising. So well done for them.
Sadly, the Navy units are less appealing, being a mixture of some absolutely excellent stuff and other aspects which are simply not really on. Navy units are sensibly constructed in the shipyard, and each side has its own unique naval force. The consortium has the more esoteric stealth ships, while the US Army has the hulking sea-hulks, and Force Talon is somewhere between the pair. Essentially, we've got the classic sea duel set up between Submarines who are good at taking down surface ship, anti-sub ships hunting them down and the heavy surface ships shooting everything else. Especially admirable, given the realistic tone of the game, is that the ships are on a far more accurate scale than most RTS games, with the camera zooming out when over the sea to show them and zooming back in when near land.
The navigation of the Navy is a little less impressive - the boarding of the transport ships is approximately four dozens times better than the recent maritime disasters in (the otherwise excellent, actually) Battle for Middle-Earth 2, but far from perfect. Less impressive is how they need to actively have their route triangulated with a second waypoint to go around any decent-sized island, which is a little embarrassing for the admiralty. This implies they haven't really reworked the AI to fit the Navy... a suspicion which really is confirmed when you discover that you're unable to play a game featuring Naval units in the skirmish mode. They're essentially a multiplayer-only addition. That there are a couple more modes for fighting other humans underlines that this is a pack that exists primarily for those who play online - and without even giving a decent experimentation zone to play with the new possibilities of the ships without embarrassing yourself in front of a peer by crashing into a pier. Or something.
Despite the gloss which defines Act of War as a game, these obvious omissions leave High Treason feeling rushed and something of a cash-in, which is something of a shame. While I'm grateful its appearance prompted me to return to the game and remind me that actually, yes, this was pretty good fun, this has little to do with the merits of the expansion pack and everything to do with the game's core appeal.