Eiyuu by TeamUDF
Eiyuu has a unique story with a cast of brand-new characters and will mainly serve as an experiment in game play, storytelling, and new items. The theme of the quest is explore.
Made for and play tested in 2.50. Playing in other versions may result in undesired consequences. (One was found in 2.50.1, in fact, so play in the recommended version, please.)
Rating difficulty on a scale from 1 (not at all) to 10 (insane), play testers gave Eiyuu around a 5. With the latest update in place, this rating should hold true for more players. Later areas can still be tricky though.
Eiyuu contains 4 to 6 main levels (it's...weird to explain) and a number of secrets that will probably be classified as "too many." There is also an experimental karma system that will keep track of items the player may have taken illegitimately from others. The karma system no longer affects any ending. Boss battles are not this game's strong suit but there are a few good ones courtesy of Moosh.
There is a small side legend revolving around 5 "mega-tier" secrets you can find in the game. Some of the higher-end secrets become increasingly abstract, but all solutions are intended to be logical and have in-game hints. I expect the player to think during these challenges.
It's very different than a lot of quests out there. It has a lot of Zelda trappings on the surface, but has a lot of really clever puzzles and breaks a whole lot of game conventions (who says the final boss can't come before the final dungeon?).
This one I have played and am interested in replaying. It's...definitely different. It's a relatively short game with a big rabbit hole of optional secrets. I love that feeling of realizing that a screen I passed ages ago that seemed completely normal at the time actually has secrets that I didn't have the context to recognize, and Eiyuu did that more than any other quest I can think of.
Spoilers, sort of about the karma system but sort of not: