We are glad that you invested so much time in our game! The map was not supposed to show the character position, since there are only 13 rooms in total and we kinda wanted to emphasize the exploration part of the game. The orb behind a circle key door is not a bug and its a fake orb, you can count the orbs on the map and see for yourself :). The point of the Death Cave is to be a misdirection and a surprise, so putting a warning would not make much sense.
We aware of the mild frustration caused by jumping and speed of the character, probably caused by the fact that some players do not know that they can hold "W" to jump higher. But again, its our fault that we did not make that clearer in the game. As for the grace jumping, well you are 100% right, that is a problem and we are going to try to avoid these types of mistakes in the future games.