Just wanted to give some quick feedback.
First of all: thanks for building all these campaigns. We've been having a blast trying to make it through them
Bug: mission 3 - When main player's ACU dies, after the mission expansion, it will not continue (since the ACU is not there to focus on). Tbh, I would recommend mission failure if the ACU dies, since technically they're controlling the army right?
Mission success and failure messages could be a little more extensive. We played for 2 hours to finish the map and when we kill the final structure or whatever and it just pops up: "mission completed [OK]" and that's it. No cut scene, no trumpets, fanfare etc. It should be important to reward the player for a victory. The explosion of your opponent in slow-motion. A message from your commander to congratulate you, or maybe a shot of your ACU(s) standing on top of a hill, looking over the victorious and ever expanding army?
When you get to the mission end stats, there's something funny going on where I think AI income is attributed to one of the players btw.
I think timed expansion / time limits can be slightly tighter to create stronger incentive to move forward: "Help I'm being attacked, need assistance", then proceed to pretty much infinitely stay around in good health and building up base defenses etc, isn't as cool as dying at minute 25 because the player didn't get any help over there. Of course, a map expand and then immediately seeing the objective getting destroyed by a soulripper before you can move your shit over there isn't great either.
Great work on the plateau on the far left in mission 3 btw. Hard to get there with exp etc. so strong spot for enemy base.
I think that if players build experimental battleship, you can maybe spawn a pretty large wave of torp bombers say 5-10 minutes into its life and try to take it down, repeating the wave again to kill it. That'll greatly reduce the power of that unit, since even with reasonable (local) air control, it can be very hard to keep it alive against a large wave of torp bombers. (We had great success with that experimental in mission 3)
Voice etc:
Since the original campaign missions have voice acting, I'd recommend you get some people to record the audio. Just post the exact dialog as you are putting into the campaign in a separate forum thread and ask for people to send their samples, with a note that they will get mentioned in the credits but otherwise have no rights on their contribution etc. You can pick the best ones, or work with the people whose voice you like most to make better quality recordings etc.
Ask volunteer from the community to help with sound engineering to make the voices sound the right way, and add the effects needed.
Other than that, keep up the good work. We're looking forward to future missions!