Trine 4: The Nightmare Prince releasing in October

Rejoice Trine fans, for Trine 4: The Nightmare Prince is going to haunt your dreams October 8th. Not only that, but the Trine Ultimate Collection which is going to include all four games in the series will launch alongside it.

Trine 3 was panned by critics and fans alike, but Trine 1 & 2 remain delightful romps for your eyeballs and solid puzzle/adventures to play solo or with friends. Trine 4 returns to the series signature 2.5D as well as featuring a revamped combat system, skill trees, and a dynamic puzzle system.

Apparently, there is coop with up to 4 players, but I don't understand how that works given there are only 3 characters in the game. Does someone play a clone or as the Trine itself somehow? 

I didn't actually see a Mac/Linux release date, so that may be releasing later than October 8th. Keep your eyes peeled on the Trine 4 website or on Steam.