Mini-games take place at the end of chapters after Chapter 3.
There are three mini-games: Table Tennis, Catch a Peep, and Heat the Bath. Select an opponent to start the game.
Once played, the combination can be played at any time in mini-game mode, and heroine costumes can be obtained by getting an S rank.

Table Tennis

Compete with the heroine in Table Tennis.
Starting from you, players take turns serving, and the first to get 5 points wins the game.
You can release a powerful killer shot by continuing to rally to accumulate gauge.

Catch a Peep

Peek at the heroines bathing in the hot spring.
Climb the cliff behind the hot spring and sometimes hide to avoid being spotted by the heroines.
You can climb the cliff by grabbing the marked rocks.
Also, the non-VR version allows zooming at the top of the cliff.

Heat the Bath

Heat the bath with the heroine in it.
The temperature will drop over time, so you will need to add firewood to keep the water warm.
If the water temperature keeps dropping due to troubles, use firewood and a paper fan, and if the temperature rises too high, use a bucket.
Be careful not to raise the temperature too high, as you can use the bucket only once.
Make full use of every item to give the heroine a comfortable bath time.