Every challenge has its own rules. If you’re creating for a specific challenge, you can select it in the studio to be told whether your creation will be eligible before you create.
Challenges that use NightCafe Daily Challenge Checks make sure a submitted creation is entirely your own work: external/uploaded start images aren’t allowed, and your creation’s evolve chain (all of its ancestors) must be unbroken so every ancestor can be checked too. The full rule list is shown while you submit your entry. (Evolve-chain checks happen at submission, not in the pre-check.)
Entries are scored on the average rating other users give them. To keep this fair, entries are shown in order of fewest votes received, so by the end of voting every entry has been rated roughly the same number of times.
NightCafe has systems to catch suspicious voting (for example excessive downvoting or automation) and nullifies those votes. We don’t reveal exactly how they work.
Some challenges use ranking instead of rating. Choose your top 10 favourite entries that fit the theme and rank them in order of preference. Higher ranks give more points:
You can also like as many entries as you want; each like gives that entry 50 bonus points. Reorder your ranking until time is up — the highest total score wins.