The reviews for Psych: The Movie are mostly positive. I agree that it was a good reunion film, better than expected. It contains a lot of the things that made the TV series successful, but did not overdo them.
It had a good musical score, which added to the story telling. Timothy Omundson as Carlton "Lassie" Lassiter had a stroke just before shooting began, so his role was reduced to a one-minute cameo. (Omundson was outstanding in the short-lived Galavant series.)
All of the scenes between Dulé Hill as Burton "Gus" Guster and his real-life fiance, Jazmyn Simon as Selene, were well-written and hilariously performed. By contrast, James Roday and Maggie Lawson were reportedly dating during the entire run of the TV series, from 2006 to 2014. I always felt that their on-screen romance was forced by scripts. I never believed that their characters would be romantically involved. As the TV movie unfolds, their characters are still not married, and she is cold to him.
Kurt Fuller as recurring medical examiner Woody Strode was funny throughout. They gave him a lot of good lines, and used him in scenes where you normally would not see him. Kirsten Nelson as Chief Karen Vick was given more to do than usual. Corbin Bernsen as Henry Spencer was used mainly for comic relief.
Zachary Levi as Thin White Duke demonstrated that he is a good actor who can perform any role well. The dream sequence, written by James Roday, hilariously indicates that it's a dream. The script pays tribute to at least three celebrities who died recently. The use of Robert LaSardo as El Proveedor was inspired writing, and he gave an outstanding performance, the highlight of the TV-film.
Surprisingly, the story did not unfold with the usual speech by Shawn Spencer solving the case. Juliet "Jules" O'Hara was more crucial to resolving things..An epilogue indicates that another Psych TV movie can be expected.