The Undead Horde (2) is marching in! The game is now available on Early Access with a hefty 20% launch discount. At this point there's only a Windows version, but a Mac version will be available at some point. Regarding Linux we think that Proton/Steamplay is mature enough so that we can rely on that for now.
We decided to make the launch discount substantial since we don't want to change the actual base price during the Early Access or after it. However, as the first players need to wait a while for the next piece of content to open, we felt it would be fair to give them a lower price since they're the first necromancers entering the world of Undead Horde 2: Necropolis.
That said, you won't have to wait too long for the new content. We'll try to release the first major update in a beta branch next week. We need to test it there for a while before moving it to default branch, but it'll be available for everyone through the beta branch in any case.
For more info on what's going to happen after the release, check out our roadmap: https://store.steampowered.com/news/app/2065810/view/3390675458878439295