Game Layout

The basic game structure is as shown

Selecting “New Game” immediately puts you at the start of the common route.
Several choices can be made throughout the common route, some more impactful than others.
The final common route choice is the fireworks confession scene where the player can choose whether or not to confess their love to Isla. If the “in love” choice is selected, the player is launched into Isla’s route. The “partners” choice leads into alternate routes based on common route choices.
Each section and their respective choice trees will be broken down in more detail below, with the Schedule Mode and Isla endings bundled in with the Isla Route section.

Common Route

The common route is split into eight segments, each mirroring their respective anime episode in title and content. The only denotation of these segments is in the save file select.
Choices made in the common route grant alternate route points. There are up to two points for each alternate route. The few neutral choices play a factor in what scenes follow said choice, which will be outlined later.
The common route reaches its climax at the fireworks confession scene, as stated above, where your choice will split into either Isla’s route or an alternate route determined by your points.
Most choices in the game affect roughly 10-20 unique follow-up lines in the short-term and the automated ending selection in the long-term, with the majority of the game playing the same regardless of choices made.
The text in a choice box will be white if it has never been selected before, and light red if it has previously been selected.

Example image where the top choice has previously been selected and the bottom has not.

There are four alternate routes, each starring a main heroine.
The routes cover alternate endings with Michiru, Kazuki, Eru, and Sherry, where an alternate ending is explored because Tsukasa chose not to confess to Isla.
These routes are not romantic in nature.
The choices in the common route that grant alternate route points always involve the heroine for that route. For example, the above picture is a choice you specifically make during an interaction with Michiru, and that choice can grant a Michiru route point.
There are up to two points that can be earned for each route, and if there is a tie for point values after making the “partners” decision at the fireworks scene, the coding prioritizes the alternate routes in this order:

Michiru > Kazuki > Sherry > Eru