In Starcraft II Is there a strategy to get all the upgrades in the Campaign

Question

I'm a new Starcraft 2 player, got it for Christmas, and Starcraft 1 was the last RTS game that I played with any regularity, about 10 years ago. I've played through most of the campaign on my friends computer, but got to the end and did not have all upgrades.

So is there a way to get all of the upgrades in the campaign? If not what are the recommended upgrades to get, and when. Also what upgrades should I balance with mercenaries? Should I save up for upgrades to things latter in the game or should I spend all my credits between every mission.

Answer 1

Although there are other answers about upgrades, I could advise about mercenaries. From my perspective the most valuable are siege tanks and battle cruiser. I would save money from hiring other stuff. They are not much better and die relatively quickly.

And in short: is it possible to get all upgrades? If in one campaign - short answer "no". But if you OK to bother with earning moneys via passing same missions 5-10 times just to get research points to be converted into money - you could try. Although I don't see any value in that.

EDIT:

Sorry. To be honest I must to say I didn't try to earn more research points. But I read that it will works ONLY after getting 25 Zerg/Protoss points. Only after that time you could try to earn more. But I would suggest to play in usual way (probably on casual level) to pass 10-15 missions and to get 1M credits. Made a save and after that do 1 upgrade line - get achievement, reload. Do another upgrades line ...