The writing and directing of the film deserves recognition; it is just the right balance of seriousness, comedy, and whimsy. However, for a film set in a mental ward it is certianly very light on the "drama" or "intensity" (i.e. this is no One Flew Over the Cuckoo's Nest or Girl, Interrupted). In fact, the hospital and its inhabitants all seem very nice and happy, especially Bobby (Galifianakis), who becomes Craig's closest friend and mentor. If people like this really are in psychiatric wards, I wouldn't mind checking myself in as well.
This film is entertaining and well-acted. Galifianakis was perfectly cast; likable, funny, and characteristically quirky. Gilchrist also delivers a solid performance and has great chemistry with his co-stars, Galifianakis and Roberts. His lead performance was believable and he brings much charisma to the screen... I look forward to seeing him in other roles in the future.
I recommend people check this one out. I doubt many will be disappointed. And if you are a fan of cheesy lip-synching there is an awesome performance of David Bowie/Queen's Under Pressure. And now that you have that to look forward to, why would you not want to see this?