The PC version of "Super Ancient Weapon Holly" has implemented an extreme challenge mode. There is also a special sale with 20% off.

The PC version of "Super Ancient Weapon Holly" has implemented an extreme challenge mode. There is also a special sale with 20% off.
 Aniplex today released a major update for the PC version of "Ultra Ancient Weapon Holly". In this update, an "Extreme Challenge Mode" has been added that challenges players to see how far they can reach from 100 levels to 1 level. In addition, a special sale is being held until May 31st where the game will be 20% off....

The linked article is in Japanese.