This is a ruin pack for the AbandonedRuins mod. It adds 23 new enemy forts with strange alien crystals that need researching if you are to utilize the crystals they leave behind after their destruction.
There are 3 new craftable items, plus a shortcut recipe for A-bombs.
The forts are designed to challenge the player but reward for success.
The recent update should mean Fortress Ruins will detect Red Dwarf and / or K2 ruins sets and include them if they are installed, just set Fortress Ruins as the default ruin set under mod settings, also K2 ruins requires Krastorio2 obviously.