This mod is fantastic, and I appreciate the hard work of the various biome authors. It really has refreshed the game for me! I was impressed with the overall balance of the biomes, this is an impressive project.

The only thing I've noticed so far is that the "Behemoth" elite from the Invasion biome seems unbalanced. He starts with a very large amount of armor and health, and if he can't be defeated before his second evolution, it seems unlikely that any but the strongest decks have any chance of surviving. Behemoth's scaling far outstrips all but the best runs, so perhaps it's worth the author's consideration. I haven't beaten him, but since he doesn't even drop a relic I'll likely just avoid him for now; it isn't a huge deal whatsoever!

I'm not sure if this mod is "open" or accepts PRs, but I'd also be happy to contribute or help in any way.