Definitely some of the best and strongest acting Keaton has ever done in a film. Pity he wasn't even nominated for an Oscar for his exemplary performance in this movie.
You've seen Guy Standeven in something because the man was in everything.

I agree about My Life! That movie was excellent! He has me crying every time I see it!

agreed he was really good

Greetings from 2015. Yes this is one his best. Along with The Paper and Birdman, which brought Keaton back into the limelight. Some of my friends thought C&S was a bit too "preachy". Perhaps, but the performances were outstanding! Morgan Freeman was kind of unknown back then too.

Although a very different type of film from the ones you mentioned, I also think Keaton gave a great dramatic performance in the Tim Burton Batman movies. He managed to play Bruce Wayne as a socially awkward, distant recluse without ever devolving into boring territory. I thought he was supremely underrated in those movies. His Batman was awesome, but his Bruce Wayne was just as good.

I have found that some comedians, when they switch to drama, are absolutely dynamite, and Michael Keaton is at the top of that list.
I have a theory that one reason good comedians are good when they switch to drama is because they are such practiced, astute observers of human behavior human behavior and interactions (and mimicry) are the mainstay of their comedic routines. In addition, they also have a very highly developed sense of timing that they use in their routines. These finely honed skills are what at least contribute to many of them being such good dramatic actors, IMO.
Keaton was absolutely killer in this, as he was in 'My Life' (about a man dying of cancer who makes videotapes for his unborn/infant son).
He had me crying my eyes out in that film.
"I will not go gently onto a shelf, degutted, to become a non-book." ~ Bradbury

Maybe the success of Beetlejuice earlier that year overshadowed this film.

Pretty good movie and yes Keaton was just awesome in it.

Keaton did get a major critics award for both this performances in this film and Beetlejuice.