ixMarcel, canteven, thank you for playing!
I went ahead and added another ending, as well as tweaking the two existing ones. The game play itself hasn't changed very much, besides a new area to complement the endings.
Current endings:
Default ending is for just delivering the acorn. Taking the acorn and then following the map gives you the bad ending. If you ignore the acorn, but follow the map, you get the good ending.
(v2 download) (http://knyttlevels.com/levels/xZilas%20-%20Woji%20Valley%20v2.knytt.bin)
There are now way more warps and flags, so there may be bugs. >(