- For the story, see Storyline.
Later in the game, the tree stops growing and constructing the Staircase in the Top Floor becomes the new objective, with similar mechanics as the tree.
A minimum rating of 61.00% is required to clear a chart. If a chart is not cleared, the rating appears in red digits and tree growth is fixed at 0.010m.
When a chart is cleared, the corresponding increase in Tree Height is computed as follows:
The Growth Bonus can only be received once per chart. It is awarded for:
The First All Charming bonus automatically stacks with the First Full Combo bonus if Full Combo has not yet been acquired.
The maximum tree growth attainable from clearing a single song is 0.650m. It can be obtained by acquiring an All Charming on the first time clearing the song and its difficulty. Without any bonus, this maximum tree growth is only 0.100m.
After reaching 20.000m Tree Height, the Memory "Blossom" is unlocked and the tree can no longer grow until the following procedure is complete:
- Clear another song to unlock the Memory "Leaves".
- Select the painting in the Attic to unlock the Memory "Where It Goes" and gain access to the Basement.
- Select the piano in the Basement (instead of selecting Play) and select Start.
- Clear the song that follows (see Basement for song and difficulty).
After clearing the song, the Memory "The New Tree" is unlocked and the Tree Height immediately shoots to 30.000m. The tree can then continue growing.
After reaching 50.000m Tree Height and selecting the door in the Upper Stairs, the Memory "You Cannot Go" plays and subsequently unlocks the Top Floor. From this point on, the tree no longer grows but a staircase progresses upwards in its stead towards a floating platform (which transports the Little Girl to the exit).
The Staircase was introduced in the 2.0 update to allow progress after attaining the maximum Tree Height. When first accessing the Top Floor, the Staircase does not exist yet but for every song Deemo plays, it gets constructed and progresses towards completion by a certain percentage.
The Staircase Height ranges from 0% to 100%. The formula to calculate the increase in Staircase Height is:
There are no bonuses. The maximum staircase construction attainable from clearing a single song is 4.000%.
- The Tree Height displayed is rounded off to the nearest 0.001m and the Staircase Height to the nearest 0.001%, but the variable storing this value has a higher precision.
- Since there is no Growth Bonus for Staircase Height, it is recommended to clear songs which have been cleared before, so that potential Growth Bonuses may be carried over to Forgotten Hourglass playthroughs.
- Prior to the 2.0 update, the maximum Tree Height was 20.000m.
- As of version 2.0, the maximum Tree Height was increased to 50.000m. The Staircase and Light Orb system were introduced.
- As of version 3.0, the Light Orb system was improved.