M'eh, wasn't doing anything atm, so I just took Terran shots now.
A typical Terran wall-in:
There's another variation where one might use 3 Supply Depots and no Barracks, or a Barracks and it's add-on and a Supply Depot.
You can lower your Supply Depots to let your guys out:
Basic Command Center
Command Center with Com-Sat:
Comsat adds Command Center abilities: Scanner Sweep, MULE, and a Supply Depot Addition. Scanner Sweep is the same as SC1, MULE is a temporary super SCV that gathers minerals faster. The Supply Depot add-on adds 8 food units to one Supply Depot.
Different Add-ons to Barracks:
Needed to build Ghosts and research their abilities. Nuke Silos are no longer added to Command Centers, but instead built at Ghost Academies. You can have one nuke per academy, and nukes no longer require "food."
There are destructible barriers that you have to watch, either because your enemy has destroyed them and they now have another way into your base, or because you see minerals/gas on the map and want to expand, but forgot there's destructibles in the way:
Not a problem for Reapers, since they can boost over walls:
The Terran Air Force
Left to right: Viking, Banshee, Raven, Medivac, and Battlecruiser. If you have them all selected like in the picture, Raven is the defualt units abilities on your screen. It takes the place of the Science Vessel from SC1. It's a detector and has no actual attack. However, it has 3 abilities: Gun Turret (on the ground, shoots enemy units), Laser Defense System (destroys enemy projectiles, about 10 per system deployed), and a Rocket which locks onto an enemy of your choosing and deals AOE on contact. The rocket lasts for (I think) 20 seconds, so if the enemy moves their unit and is chased by the rocket, it's possible to not be hit at all.
Terran Vikings can change to land or air