Trine 5 will be released at 31th august and it will probably a as exiting coop experience as the past games.

I heavily recommend Trine 1, 2 and 4 to play with one or two friends. Of course the games have exiting coop mechanics, but for me the fun comes from it to break these puzzles with your friends. Sometimes you don’t understand some riddles but you will find a way to solve it and it’s always fun to get through it together.