Been playing through this on hard and haven't had too much trouble so far, made it up to Cybran mission 2 which is a very weird mission and I kind of like the idea though there's problems with the execution. The basic framework of the mission is that the AI sends mass engineers to capture your base, I gather you're supposed to counter this by out capturing them with your own engineers. However engineers do not automatically capture as the AI does in this mission so you basically have to micro every individual capture and the AI does it instantly (in previous supcom games multiple units could capture/repair one unit at a time but now its just one for each), you can outnumber the enemy engineers and do it that way since usually the captured engineers will be somewhat stupid on their spawn but once you hit a unit threshold (25?) on hard the AI starts sending waves of 8 engineers from multiple directions. So the only way to actually beat it on hard is (basically) cheat and make a naval factory out in the great blue yonder and very very slowly build up a naval force; engineers can capture your naval units as well but not fast enough for it to matter (early ground units are capped ridiculously fast and you can't get enough point defenses up before the engineer zerg comes for your soul).
So what I did was make a base at the start to generate some resources and build the aforementioned naval factory; I then salvaged my own captured base since engineers can't do shit to your ACU and there's no point defenses near where you spawn; I salvaged enough to make about 5 battleships and 8 destroyers and then did some more salvaging; I then started to take the naval route to the enemy base which caused the AI to try to defend itself with engineer waves; but battleships take too long for them to capture so I was fine. However they had a limitless supply of the damn things so I couldn't really make much forward progress without even more battleships and decided to rebuild my base since the AI couldn't pump out enough engineers to re-capture it. Then the game started freezing because the AI couldn't handle this result and really really wanted to do both things at once; it was amusing because it is basically like the game is paused, can still go around and issue commands just nothing happens for 3-4 minutes at a time then the AI figures it out for about 5 seconds and then it freezes again. I'll do this mission again the very very slow way and rely solely on salvaging/ACU resources, but it's kind of funny that the game cheats so I cheat back and then it says fuck you and cheats right back again by freezing it.
Fun game nonetheless though a little less grand in scope than the previous renditions (Forged Alliance fixed most of the UI/pathing issues and gave you hugeass 4 hour levels to play around with, not to mention the experimental infinite resource factory of hilarity). So far the unit cannon is by far the most interesting new thing but it does manage to feel like Sup Com and fairly unique in the clone-ridden RTS landscape. The same "Build beachhead, defend, mass units, attack" methodolgy works but it's slightly different since there's no godly T3 things to simplify how many units you need. Unit cap is a non-issue if you play the game correctly (they're all robots after all, they don't have feelings or families to be concerned with, rated E for everyone!).
Note you can probably beat it with overcharge on your ACU as well but that's probably more time consuming since you have to wait for enough energy/regenerating to power through about 5 lines of turrets and maybe even more cheesy since you're only using one unit.