If you defeat it after stage 2, you will be sexually punished by the boss.
Even if you lose, you can get experience value and money and you can return to the base by retreating without rematching.
You can open a treasure box (reopenable), save it, purchase items at the base between stages.

Once cleared the reminiscence mode is released,
You will be able to see defeat scenes and dot drawings from the title.
Also, once you clear the game you will be able to skip the conversation with the A key.

Necessary Settings
The application may not function unless a Japanese language pack is set properly in your PC / the System Locale is set to Japanese. For more details, please refer to [ How can I set my system locale to Japanese? ] on the Frequently Asked Questions page.