First - I am so glad to see this game progressing to a final stage AND that it resembles so much of what PG was. I cannot remember how often I played PG, AG and PGII until it became more and more troublesome to get them running on state of the art rigs.
Anyway my first impressions after just playing the first poland scenario on v 0.99 :
What I immediately liked:
+PG feeling overall
+combat losses well balanced and not too high as in other hex games (where a single unit attack would wipe out an entire unit) - but will have to observe this further.
+difficulty on seargent (2nd difficulty is OK) finished the first scenario in 9 turns with no total unit loss - despite my complete lack of experience with PzC.
What others already posted as problematic:
-I agree with RobertCL about the colors being too "green" for the country and the purchase windows being too "dark" in contrast. I think the original SSI PG coders made the "fade" green and very light grey tones on purpose to avoid that.
-I agree that highlighting the currently attacking/attacked unit should be done/improved somehow. Hard to tell whats going on during AI turns.
What is missing/should be added or changed IMO:
1) Please give more information on the differences of the difficulty levels, for example a pop up telling what the advantages/disadvantages of AI will be. Is there a "neutral" setting difficulty ?
2) I cannot distinguish CORE and AUX units. I hope this is not intentional ?
3) Please enlarge the golden bars around the flag icons in victory hexes or make them somehow more "perceptive". Perhaps enlarge all flag icons in size on hexes ? I find them too "tiny" atm.
4) I am definitely missing any kind of "information" bar showing a short summary of the combat events. Currently combat just takes place and you have too look very closely on what really happened. In PG there was a small "notification" bar at the top part of the map where a summary of the combat was posted like "ATT: 5killed 3 supressed - DEF: 0killed 2 suppressed
5) Pioniere and similar infantry ignore entrechment is that correct ? If so it would make sense to make an additional icon (or text) to show that capability on all unit related parts (at least add this to the purchase window)
I assume other units have "special" skills as well - so these should be shown somewhere definitely.
6) The Pz IIIE is not purchasable ? Not even in Poland, shouldn't that be purchasable there ? What about (early) Pz IVs - at least in Norway ?
7) Does upgrading really cost the same amount as if I purchased a new unit ? Especially harsh I find as I also loose all experience AND overstrength and do not even get the prestige for the old unit back. IMO a little too harsh, at least give a price discount on the unit or do not loose ALL experience.

9) I can't tell what the difference between Tactical Bomber and Strategic Bomber is - apart from different stats values. Is there any difference ? If no difference why keep 2 different unit classes in the purchase menu ?
In PG Strategic Bombers reduced enemy prestige when bombing cities - is that valid in PzC ? Can't tell since no "combat feedback" whatsoever is obtained during game and the ctrl+click previes does not mention anything extraordinary like that.