I've emailed the company which owns the game and they've directed me to just download the game from this link.

Download DOS version

If you download the game (better performance than web version), use DOSBox to emulate the game.

Download DOSBox

You can play the full version of the original DOS game here.

名前	マネージャー
Download DOS version 投稿者: myabandonware	Ms_Riley_Guprz 2 years ago
Download DOSBox 投稿者: DOSBox	Ms_Riley_Guprz 2 years ago
Link to the full game online 投稿者: Classic Reload	oddtom 5 years ago