The Fallen Citadel is a 3 wool map that uses 1.12's new advancements system to provide a series of optional challenges that task you with beating the map while also meeting certain criteria. Other features include a loot system based on one of my previous Jam entries, 'The Null Machination', and a lives system that puts you in a Game Over state if you die too many times.
Full Advancements List:
A Whole New World - Begin the map.
Hey, A Shiny Thing - Find a Power Crystal.
Wool Get! I - Recover the Green Wool.
Wool Get! II - Recover the Red Wool.
Wool Get! III - Recover the Black Wool.
Veni, Vidi, Victory! - Beat the map.
Underpowered - Craft an Emerald Block.
Boom Town - Beat the map without killing any creepers.
Into Darkness - Beat the map without placing a single torch.
Melee Master - Beat the map without firing a single arrow.
Aced - Beat the map without dying once.
Speedrunner - Beat the map quicker then BSM [me, the mapmaker] could. [500 Seconds]
(Technically my time was 499 seconds, but I just decided to round it.)