Week of.. , well. They opened site and discord. If you have any questions, you can just join them now and ask, see links at the end. 
The game is originally scheduled to appear at Kickstart by November 2022, you can subscribe to watch it.
- The game is described as 1-3 players, 45-130 mins, recommended age 14+. So far they are not considering to release also version without miniatures (minis).
- Core Box Factions: Castle, Dungeon and Necropolis
- Gameplay is limited to one hero per player. You can also develop one town only (mechanical limitation), but you'll be able to conquer other players' towns. Furthermore, you can find settlements on the adventure map (as you may remember from "Heroes 3," they're some "minor towns") that will bring chosen benefit. :-)
- There will be 2 heroes per each faction (1 for Might and 1 for Magic class).
- Movement on the adventure map? Heroes will have movement points - they will have to spend 1 point to move 1 field on the tile, or to discover a new adjacent tile.
- The "Fog of war" system is already developed. Some tiles would be faceup from the beginning of the game; during the game, heroes will discover more tiles and "build" the map through their movement.
- To reduce downtime in the 3-player gameplay: At the same time - the first player is performing PVE, the second is controlling the neutral creatures in this PVE, and the third is building structures in their town and recruiting units. :-)
- One mini per each faction creature and two heroes' minis per faction. Neutral creatures could be depicted in another way.
- Oh, "Astrologers proclaim," events will be resolved at the beginning of every second round.
This text was gathered from BoardGG forum, replies by Jakub Olekszyk Archon’s Lead Game Designer.
You can take a deeper look in at their "Designer's note on HOMM3 Board Game gameplay" newsletter entry #1.
BoardGG | Discord | Images Gallery | Blog | Our Thread