Hi, one of the original QA testers for MSC here, and someone who has been... very, very involved in the making of this. To say I'm biased is an understatement, but I just want to put this review out there, that this DLC, particularly the new slug cats and their campaigns and regions, were made with so much love, care, and attention. It's still so surreal to me to be able to write this review, for nearly 4 years now it has all been hush hush keep it secret keep working away, and now I can just, publicly share it all.
Also Gourmand is best slugcat. Because he's fat and not because I was the one who helped design his original campaign concept.
I do hope that if you are uncertain about this, but enjoyed the base game, this is just more of that, I would honestly consider it the definitive rainworld experience.