Following the release announcement and early details of the upcoming Heroes of Might and Magic: Olden Era, developer interviews and previews have unveiled a lot of new information about the gameplay and game mechanics.

Q&A with Unfrozen Studio (English)
Q&A with Unfrozen Studio (Russian with English summary)
Q&A with Unfrozen Studio (Twitch, English)
Preview in Polish
Preview in German (English subtitles)

Details from the developer interviews:

• HoMM: Olden Era began development in 2020.
• Early access is set to release in Q2/2025, with full release in 2026.
• The early access version could have been a full release in terms of content and features, but the team wants the players to give feedback and make sure the final game is polished.
• The game will initially launch on PC, with potential releases on other platforms later. Cross-platform support is planned.
• Six factions will be available at launch, with more to be added post-release.
• Free content updates and expansions will be provided after release.
• There will be paid DLC, but no microtransactions.
• Developers have consulted with professional players and the community throughout the delevopment and will continue doing so.
• While competitive multiplayer has been a major focus during the early development, there is also extensive single-player content.
• Single player mode does not require an online connection.
• Multiplayer features will include simultaneus turns, a draft system, turn time limits, ranked/non-ranked matches, skill-based match making, replay recording, anti-cheat tools and observer mode.
• There will be three multiplayer modes: Classic, Duel, and Arena.
• Special events and tournaments are planned.
• Game statistics will be collected and reviewed to balance the game through hotfixes.
• Hotseat mode will be included.
• The campaign will be non-linear, with the first act releasing in early access and offering about 6 hours of gameplay (approx. 1/4 of the whole campaign).
• A map editor will be included in the early access version.
• Developers are putting significant effort into the random map generator, aiming to make it as balanced and bug-free as possible.
• Town screens will be animated.
• Maps will have underground levels.
• Units will have two upgrades, and players can recruit both upgrade versions.
• Units collect energy during battles, and can use abilities when their energy meter is filled up.
• Classic war machines won’t be available for every faction, but they will be included in some capacity.
• The morale system will have five levels (+/-), affecting whether a unit has two actions or skips an action.
• There will be a Grail system, though it will differ from previous iterations.
• New skill system for heroes, with each skill offering five passive effects.
• Factions will have unique skills with passive effects for heroes.
• Diplomacy will be included but will function differently than before.
• Two types of heroes: warriors and mages.
• Spells can be acquired from towns or various locations on the map.
• There will be more adventure spells and spells outside the main magic schools.
• The game will feature item sets.
• Developers are emphasizing game performance, ensuring it runs well even on low-end computers.
• Mod support is planned but will not be implemented before the official release.
• AI behavior will differ between the campaign multiplayer modes.
• AI will be capable of using both primary and secondary heroes effectively.
• New economy and city management systems.
• Music will be a mixture of old and new, but no confirmation if Paul Romero is involved in the project.