My friend said that the easiest way to get that achievement (destroy 50 Protoss buildings) is to scan with the Orbital Command and then laser everything. Unfortunately, I didn’t have Orbital Command when I did that mission. I can’t remember if I had Vikings though. I’ll try that.

I finished the campaign last night. Without spoiling, I think the “non-linear” structure is its biggest problem. Three of the four storylines just dead end. It’s like, why did I waste all this time helping colonists or doing Tosh’s missions if there’s no payoff at the end?

Mass Effect 2 handled this better. It felt like all the time spent collecting teammates was worth it, because they all have different roles to play in the final mission. (I would’ve liked it if there were a few more choices to make in that department, but that’s a whole other discussion.)

I’m still playing the challenges. They’re great fun. I managed to get perfect on the first Protoss one too. It took many, many tries. Tip: You can save during challenges, so you don’t need to reload the whole round if you screw up the end.