Anyway, when you play this game on hard or brutal do the tactics change from the enemies or do they just rush more units? They don't handicap your units and call that hard mode? What changes on the harder modes exactly?
The unit composition changes which can make things very difficult. I recently started going through missions on brutal and on the second mission where you attack the dominion base after just having gotten medics, there was a siege tank defending.
The ai changes its targeting priorities as well. On the thor mission if you are playing on hard the enemies will ignore your scvs repairing and focus fire on the thor, on brutal it is pretty much vice versa making keeping him alive quite a bit harder. Generally it seems like the ai goes after your scvs much more often making previously easily accomplished things like keeping bunkers repaired challenging. You can also expect that the enemy will take out your medics if given half a chance.
I also noticed that they removed or increased upgrade caps for the enemy in a lot of missions whereas before you would be fighting on at least even footing but on brutal you can often be against 3/3 upgraded units while you are 2/2
I played against the highest level difficulty ai in a 2v2 with a friend just to see if we could turtle until we teched to formidable forces and had my socks knocked off when the ai sent in a force of 5 reapers who bypassed our front door, jumped over the wall next to my probes and demolished them. I sent my mobile force to attack them and they ran away with minimal losses. Amazing!
Needless to say, we could not beat the ai on that setting.