More Slugcats Expansion is a massive expansion to Rain World, releasing as part of Rain World Downpour. More Slugcats adds five new playable characters, each of which has their own storyline, are unique in their abilites, and unique in their spot on the timeline. As a result, there is a lot of new content exclusive to each playthrough. There are new creatures, items, music, alternate endings, as well as 10 new regions spanning over more than a thousand new maps.
This expansion not only adds content, but tackles the base game as well, with quality of life gameplay and mechanical fixes, bug fixes, performance improvements, and other such tweaks and polish to address some of the frustrations that were cited by players and reviewers. It was made with love and passion by a community of Rain World fans who want to see the game equally loved and appreciated by a wider populace.