At this time little official information has been released by Blizzard about the Terran units, so this list has been compiled by viewing gameplay footage and leaked sources.

Marine

What would StarCraft be without Terran marines doing battle against the Zerg? The marine reappears in SC2 serving what seems to be the same role as in the original. The most versatile base unit, the marine has the ability to attack both land and air units making them not only an early game force but a mid to late game threat as well.

At the moment marines seem to be playing more of the role they had in the original StarCraft as opposed to Brood War where they were almost always accompanied by Medics. Medics may still be included in SC2, but at the moment they are not.

Gameplay footage shows marines support siege tanks as they did in StarCraft against masses of zerglings, but what is a bit surprising is that it seems that marines will play a bigger role against larger units in SC2 as well. Footage shows a group of marines taking down warp rays, a deadly Protoss air ship.

Reaper

The reaper is a brand new unit introduced in StarCraft 2. The main quality of this unit is its speed which will make it the ultimate Terran harassing unit. The reaper has a fairly weak, short range attack which makes it unsuitable for face-to-face large scale battle. What it does have, however, is the ability to quickly move around obstacles by using its jet pack which can propel it over cliffs and onto ledges.

Although the reaper may not be a game-changer unit on its own, it will be great for stopping those annoying tank drops and harassing unprotected workers that you thought were protected by natural landscape.

Ghost

The Terran ghost is back, but this time he seems to be wearing a tight, white, spandex suit. Whatever the wardrobe, the ghost is a force not to be underestimated. Not much has been revealed on the ghost’s place in StarCraft 2, but screenshots have shown nukes exploding and ghosts cloaking. It may also be safe to assume that ghosts will retain their mechanical unit crowd control (Lockdown) with all of the high tech Protoss warships flying around.

Siege Tank

The Terran siege tank is certainly one of the most important units in the StarCraft universe. In the original StarCraft, the siege tank made an appearance in nearly every single game of every single matchup. Whether it played the dominant role, supported a marine push, or was used to harass helpless enemy workers from afar, the Terran siege tank was a force to be reckoned with. From the current gameplay footage and other unit information available, it is safe to say that the siege tank will be equally as important in StarCraft 2.

Update: Karune has announced that the siege tank has been remodeled and will be unveiled at Blizzcon.

Battlecruiser

The flagship of the Terran air units, the Battlecruiser is back and badder than ever. In StarCraft a group of battlecruisers could lay waste to entire armies. With enough cruisers, not even scourge could match their air attack. Although the battlecruiser is back in SC2, a lot has been changed.

Probably the most confusing aspect of the BC in StarCraft as the fact that it was a gigantic warship that focused almost entirely on one-on-one combat - meaning it shot one laser at one target. That being said, a little squad of marines and one medic could easily lay waste to a battlecruiser because it could only kill one at a time. This is a problem that seems to be fixed in SC2.

Not only can the new BC attack multiple targets with multiple shots, it also has a new AOE (area of effect) special attack which will replace its Yamato Cannon.

Thor

Thor is a brand spanking new ground unit for the Terran army that will further add to the Terran’s ground domination by being the ultimate ground-to-ground barrage unit. Although Thor hasn’t been seen in action by the public, screenshots show it dominating swarming enemies with an explosive airstrike.

Although Thor means serious business, don’t call it a “superunit” as the Protoss mothership is the only confirmed superunit in the game.

Viking

How can a futuristic human race exist without inventing a machine that can transform from a ground unit to an air unit to wreak havoc on all fronts? It can’t. And Blizzard finally figured it out. The viking is a transforming unit that can act as a ground unit or an air unit. It is doubtful that it will be extremely good at either, but the versatility of being able to go from ground to air is not to be underestimated.