Wellington said:
The tech tree is impossible to figure out, that's my problem.
What is bad about Thors?
You can google for the other races but I figured you will be playing Terran for a while to learn the game as most people do.
Thors are fine for anti-air but only for light aircraft, and Thors kinda need some support (marines). I was bringing in battlecruisers so by that point, your options are to either match me with your own cruisers, or go ghosts and Lockdown the cruisers (or maaaaaybe stimmed marines with Medivacs).
The basics thing about the tech tree is, don't climb too high (or out on a limb) too quickly. While you may get advantages from having more powerful/specialized units, you also will not have basic units to defend your own base or scout for your opponents main base+expansions. From that picture, the further down you get in the middle, is "climbing." I know that's counter-intuitive; the older tech trees were laid out in a way that went from bottom to top and fanned out like an actual tree, but you get the idea.
Anyway, you basically want to ensure that you have a standing army to defend/attack at a moment's notice. You want to try and upgrade and anticipate your opponent's strategy (is he going air, specialty units, etc) while simultaneously harassing their base/economy so they acquire resources slower than you and have to waste valuable time addressing your attack/fixing their economy while you continue building units/climbing the tree.