With the release date of Supreme Commander 2 creeping ever closer, the game's developers,
Square Enix saw fit to release two unit profiles to the public. These two units are the ACU and the Engineer, arguably the two most important units in the game.
The Armored Command UnitThe single most important unit in the game is the ACU. In a nutshell, you are the guy/gal inside this unit. It has been the single most important unit on the battlefield in past Supreme Commander games and it will be making a return in Supreme Commander 2. The ACU is your primary builder unit, it has the ability to construct all the buildings you need in order to get your war machine rolling. The ACU itself is also a powerful weapon platform in the early stage of the game and can be upgraded to be even more destructive or it can be upgraded to build faster or produce more resources. You can also fit it out with defensive upgrades. It is worth noting that you should take great care with your ACU, its destruction creates a powerful explosion which decimates everything near the ACU, not to mention that losing this unit means the end of the game for you.
Initially developed by the Earth Empire as a practical solution to the logistical nightmares and prohibitive mass costs of teleporting large armies across the galaxy, the ACU is now considered the most recognizable, powerful and flexible weapon in the galaxy. A low-mass high-capability unit easily transported across the quantum network, the ACU weds cutting-edge military science to the latest breakthroughs in nanotechnology to achieve a combat potential greater than any force in history.
Source: Supreme Commander 2 Official WebsiteThe Engineer is among the most useful units in the Supreme Commander franchise. It has several abilities that make it vital to achieve your goals. The Engineer can construct buildings and repair them, but it can also reclaim units, structures, wrecks, trees, rocks and many other things. Reclaiming takes the mass and energy from the item being reclaimed and adds it to your storage. Therefore, it is always useful to have engineers on the map ready to reclaim wrecks after a battle. The engineer also has the ability to capture enemy units and give you direct control over them, why destroy a mass extractor and rebuild it for resources when you can capture it? Adding to their versatility is the fact that Engineers are also amphibious and can travel across water.
