Yo, let's go in order:
1. Mushroom forest
I added it purely for biome diversity, but honestly, I feel like the mushroom forest is a candidate for being cut from the game. A magical forest with crystals sounds cool, but a mushroom forest... I mean, maybe I could come up with some small faction/people living there that you could trade with, etc., but for now, it's better to treat it just as a quirky decoration.
2. Necropolis
The Necropolis is a crucial part of the game's story. I'm thinking about adding a toggle for sandbox mode so players can disable its spawning, but as for destroying it in the campaign... I think that will be one of the major story-driven choices later on.
2.5 Enemies
I already have some ideas for new enemies, but they aren't mushroom-related :D
I don't want to reveal what I'm planning just yet since it would be a bit of a spoiler, so let's just say it's to be announced. For now, I'm going to develop the undead theme for enemy raids. There's still a lot of cool stuff I can do with them so that undead raids feel like a proper challenge for the player, rather than just a couple of mindless bots rushing you (though the first few raids will look like that).
3. Factions
There won't be a faction swap feature in the game. It's an interesting concept, and I could technically implement it, but I want to keep this game focused as a classic "settler" city-builder. I have tons of ideas for other strategy games where faction mechanics would fit perfectly, but I don't know when I'll actually get around to making them.
Building Ideas:
- Harbor: Interesting idea! I'll take it into consideration and look into it.
- Various crops: Another one awsome idea! But i guess different crop types should provide various bonuses to settles. So will work on it.
- Barracks
The idea of connecting them to walls sounds really cool. As for the barracks themselves and controllable units, I’ve actually already implemented them. The only reason I haven't added them to the game yet is because I'm having some trouble with the visual assets. Or rather, the lack of them. I’m currently using an asset pack for sprites that doesn't include any human warriors or mages. Because of that, I've put this feature on the backburner for now. - Portals: These will be added to the game very soon. To be honest, I've already coded them!) They just need a little bit of extra polish.