A Challenge is the other thing you can place on the Journey Map alongside a Milestone. Where a Milestone provides knowledge, a Challenge tests it.
There's a Right Answer
A Challenge is a quiz. You build a bank of questions, and each attempt shows a subset drawn from that bank — set how many questions appear per attempt and how many correct answers count as a pass. Add an optional time limit if you want it to feel like a real test rather than an untimed review.
Attempts & Retries
Challenges can include a number of free attempts, with additional attempts costing BLOO beyond that — useful when you want a real assessment (limited retries) rather than something a player can brute-force by retrying indefinitely for free.
Challenge or Milestone?
If a player could plausibly fail and be sent back to try again, build a Challenge. If they just need to go through the content — even content that asks them questions along the way — build a Milestone. A Milestone can absolutely contain Multiple Choice, Keyphrase and other Validate steps that must be answered correctly; the difference is that those gate a single Step, while a Challenge grades the whole thing and can be failed as a unit.
In Launch Week
The Week One company-policy quiz is a Challenge — five questions per attempt, four correct to pass, two free attempts, a small BLOO cost for a third. The end-of-Week-One "How was your first week?" check-in is not a Challenge: it's a Milestone built from Rating Scale and Open Text steps, because there's nothing there to get right.
Where to go next: How to Build a Challenge.