Secret Window is Stephen King done right (the film is based on a King novella.)
Johnny Depp plays the role of Mort the author very well, and John Turturro is excellent as the dark one who appears accusing Depp of stealing his story and publishing it as his own.
I cannot say more without giving things away.
The genre is horror/psychological thriller. Look for Hitchcock and Alice in Wonderland references and all the usual suspects and ingredients. I think you get your money's worth if this is your cup of tea.
No, not an Oscar contender (I don't think) but Depp is very very good and appropriately funny at times - not quirky. The King-Depp combo is good.