The Chrono Trap DLC brings a new Endless Mode and the Titan, Chronos, to Neon Abyss.

Endless Mode: Face down endless challenges and new elite monsters to unleash your full potential. It's a perilous journey to your final battle against the all-powerful Chronos! How long will you last?

Chronos: Upon purchase of the Chrono Trap DLC, you will be able to challenge the new Chrono Titan in two different play modes!

How to begin the Chrono Trap adventure: There is a play mode switching device at the edge of the cliff by the bar. Change the mode to ‘Endless Mode’ to gain access.

More details on the official game page of Neon Abyss - Chrono Trap ...