Depending on your luck with the randomly placed key-cards and robot AI (whether you get the T-800 chasing after you or the Furby with one droopy eyelid that doesn't blink anymore) it will take somewhere in the neighborhood of an hour or two. And when it ends, it ends. As soon as you escape the police station it goes straight into a white dissolve and a logo splash screen. No epilogue, no wrap up, not even a voice over.
CASE: Animatronics has decent atmosphere and unintentionally hilarious voice acting, but nothing really stands out, and most of the game is filled with boring and familiar horror cliches.