I played the Axis campaign at intermediate and conquered Russia late 42.
I'm the middle of playing Allies now at expert. Axis still took lenningrad
on me.
AI is a little better but still attacks when it shouldn't..like all AI does.
Since the game plays quick (rather keep playing turns for hours on hours) it
may not have a zillion replays for me..but I get bored after playing a few
times the same game anyway.
Negatives: These are short.
I still hate coastal bombardment.

So don't park stuff on the coast. I
suspect a human won't randomly bombard you The interface is fine..more than
quick enough.
Positives.
The squares didn't bother me when I first saw the screen shots as I figured
it was part of the design. It is. Better frontage to attack now since you
have units that represent armies and there's no stacking. I have them on and
you barely notice them they're so light.
The graphics are actually outstanding. Unlike the demo, you can turn both
types of unit bases off to no base. With nato counters you hardly even
notice it's 3D.
The biggest improvement is there is now a counter mix. No more building 20
airplanes. This gives much more a feel to a wargame. Also with delayed
production you have to think ahead.
The upgrades are nice too. You can either put reinf or upgrade in the field
but not both at once.Decisions when to do this make for much more strategy.
Do you reinf and not move. Wait and upgrade and not move the next turn....
Elite reinfs go by medals won so not every unit can have 12,13,14's etc. My
best tank unit was 15 with max Hvy tank at the end of the war...but it had
seen all the campaigns. The types of upgrades and limitations are real nice
too.
Enginners are great and can build forts. You even choose how many sides..the
more the longer it takes.
Ehypt is now much better with room to manuever.
The airborne is nice but not exactly deadly. Still can come in handy.
Diplomacy is much like 3R tho I haven't used it. (I always go brute force
anyway)
Naval is about the same.
While still not hardcore what he's done with the sequal is turn the beer and
pretzel SC1 into at least something more like a wargame.
You can even have a ship get damage in rough seas.
This is a great fun game and highly recommended.