I enjoyed playing your game a lot. Managed to find all 12 endings (with some generous help from the hint giver you provided). I think I also found the secret ending too.
I really liked how you made subtle variations on the same Music track for each area. Transitions between areas were really well done in general. As was the art style, particularly the underground area with its mood lighting.
Only improvement I can think of is maybe adding a reset button. Sometimes I would explore parts of the Underground and get stuck, forcing me to complete a load of jumps just to reset the game.
Very polished and well made game. Congratulations!