The free trial allows players to do anything they'd like to in the game during that three-day timeframe, and it comes with special bonuses for the super-ambitious. Participants who complete 30 missions will see their free game time be extended to a total of five days and be treated to 1200 points to spend in the game's store. Additionally, anyone in the trial who tackles and beats the Polaris dungeon will receive a Whispering Demon Ring for free.
The signup for the trial is on the front page of the official website.
