So far I've done all the tutorials, the campaign mission, and beat a survival map on Hard.
The tutorials were surprisingly fleshed out and non-trivial to complete. For something labelled "tutorial" they were a surprising amount of fun, and they were a solid introduction to the streaming economy and its wrinkles - the power stall tutorial in particular was just a great concept.
I really wasn't expecting to be seeing, let alone killing, a Titan in the very first mission. Maybe that's the influence of the devs knowing the mission would be their Kickstarter showcase. It was a fun mission though, and I appreciated it was both objective-based and gave you a decent amount of latitude in how you reached the final victory condition. More design like that, please!
The survival mode could use some signposting for where the enemies come from - there's not really much point in not making it explicit, seeing that once you've played it once you know exactly what you're dealing with. Also, at least on White Sands, the mass extractors nearest to the enemy spawns were a bit frustrating - to keep control of them, you need to establish defenses far enough forward you'll need to fight and kill enemy arty and T4s while they're still slightly off-map, which is awkward, a bit unsatisfying, and makes reclaiming even harder to pull off. For all my picking of nits, though, the mode was fun, challenging, and definitely the part of the demo I'll be revisiting the most. I desperately hope the mode will support multiplayer in the full release!
Enjoying the demo and looking forward to what comes next.
P.S. for context, I'm a Supreme Commander veteran (my buddy and I are replaying the FA campaign co-op through FAF right now, in fact), but haven't played BAR or any other SupCom-adjacent titles.