Time-based, subsectioned, configurable quest system
The TotR system has a notion of "regions", which contain "hubs", which contain "challenges". Rewards are on a hub-by-hub basis, and only 2 hubs can be simultaneously unlocked/progressed.
The UI components and data are neatly separated, so that the same UI components can display the information for different regions/hubs/challenges.
Each region opens at a different time, so the player should only be able to access regions that are currently available to be unlocked, but should be able to see all regions (and when they unlock). An item, active or inactive to indicate when the region opens, can be scheduled by designers.
Players have tickets (a new currency created for TotR) they can spend to unlock a hub. From a technical standpoint, players "have" all hubs (quest groups) that are scheduled, but all progress is gated by a challenge (invisible to the player) that is only completed by "purchasing" the hub unlock item with a ticket.
The completion state and progress of each region/hub/challenge is tallied and displayed to the player.
Lore blurbs, region titles, and region order are all configurable by design.
Vatu
Flank champion
Client-authoritative (but server validated) chain teleport attack
Delayed-explosion bombs that stick to the environment and will fall off shields that are retracted
Ultimate that uses start/stop button presses to acommodate gamepad players. This was new technology added, now usable by other devices.
Dash ability that maps off combinations of character view and player input
Triple projectile spread attack
Coordination with other teams for triggering sound and visual effects and transitioning animation states
Azaan
Frontline Champion
Multi-wall place ability; 3D math to find focal point for walls, project wall positions, and account for ground and if terrain has room for that segment.
Ultimate ability where Azaan throws a hammer that unleashes an explosion, pauses, travels quickly to the hammer, and unleashes a secondary explosion. This ability has many sub-states (flying, aiming, throwing, lerping, finished); timers and fireloop triggers are used to manage animation states, camera viewpoint, and status effects on Azaan. This ability also uses 3D math to find appropriate locations for Azaan to travel to
Rectangle shaped attack that pierces geometry. This ability shoots a projectile that "bursts" into a rectangle at its endpoint.