Other Secret unlockable end themes

[Methelin]

Basically, if a player performs some secret challenge in game (variable in difficulty, like "Rightfully kill 10 innocents in a single round", "Survive 3 minutes as an innocent with less than 20 HP", "Survive the round as an innocent being wounded by 3 different traitors", "Perform the round-winning kill within 5 seconds from round start" etc.), either a secret end theme - fitting performed challenge - plays or the player is rewarded the theme as an inventory item to be usable anytime in future.

Example 1: A traitor is on a killing spree and killed more than 10 innos in one round. They are rewarded with the drop from JACKNIFE's "Rapture".
Example 2: An inno is lucky enough to survive 3 killing attempts from 3 different traitors. They are rewarded with the drop from this epic track with long-ass title.

If the theme is played everytime a challenge is done, it could be a kind of an event, making people try their best.
If the theme is given as an item to whoever completes a challenge, these would be valuable and desired, given their obtaining would require a large amount of either luck or skill.
Or it could be both.

 

[Opalium]

This is very similar to the achievements system we have in the works. Correct me if I misunderstood, but by "secret", do you mean the reward will not be known until received?

 

[Methelin]

I thought more of that the challenge itself is secret, just like there are secret achievements in some games. These however could be made known with the rewards being secret, just as you said, as they are rather normal, while some unusual ones could be actually secret, like "Kill at least one player of every role (innocent, traitor and detective) in one round", as it would require at least one RDM to be made to be achieved, and we wouldn't want people to know there is an achievement (although with a reward - again a special end theme) that is obtained via disregarding the rules.

Just an idea though.