I recommend buying it when:
1. It's on sale, which happens a lot.
2. You already have Back to Ubersreik, as it's regarded as the better dlc.
Both levels are good, although the second one is disliked by some. They differ a lot from the rest of Vermintide, and there's a lot of interesting situations that change how you play the game. Stuff like having an "open" level with differing pathways, or areas that are too dark to see, so someone has to carry a torch (this one is a bit controversial).
So it's very hit and miss for most people, which is why I recommend getting it on sale.
izigame.me
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