Ground units:
The Marine, to build marines you'll need barracks.
It has 40 hit points and gives 6 damage, with a bonus of 1. The Marine works best in big groups
or in bunkers.
The Firebat, to build Firebats you'll need barracks.
It has 50 hit points and gives 16 damage, with a bonus of 2. Firebats can only fire on ground units.
The SCV, or the "worker". This is the first unit you can build.
You'll need a Command Center to build a SCV. It has 60 hit points and gives 5 damage, with a bonus of 0.
The SCV is not made for fight, only working.
The Ghost, to build ghosts you'll need barracks and science facility with covert ops.
It has 45 hit points and gives 10 damage, with a bouns of 1. Ghosts have some special abilities:
Lockdown: Can only be performed on machines. Target get locked and can't do anything for a while.
Cloak: The ghost gets invisible, except for detectors.
You'll need to research those things a the covert ops. before you could use them.
Nuclear strike: You'll need addon the nuclear silo to the Command Center. The ghost can blow of a nuclear strike. It clears almost everything.
The Vulture, to build vultures you'll need a factory with a machine shop(if you want to upgrade).
It has 80 hit points and gives 20 damage, with a bonus of 2. Vultures can only fire at ground units. It also have a special ability.
Spider mine: Lay out the mine with the vulture, The Spider mine has 20 hit points and gives 125 damage to anyone who steps on it.
The Goliath, to build Goliaths you'll need a factory and an Armory.
It has 125 hit points, gives 10 damage to ground unit and 20 damage to air units. The bonus is 1 and 2, it costs 100 minerals and 50 gas.
Goliath works in all situations.
The Ziege Tank (tank mode),
The Ziege Tank (ziege mode),
Air units:
The Wraith,
The Dropship,
The Science Vessel,
The Battlecruiser,
Please mail for comments or questions, or if you need help with something!