Psycho is a graphic adventure game with a key-based verb interface.
A set of jewels has been stolen. At the time of the theft, a curator was with the jewels, so he got stolen, too. And who's the suspect? Norman Bates, of course. The next night, a daring detective drives out to the sinister Bates Motel. His plan: a) find the jewels, b) free the curator and c) take a nice hot shower, should time suffice.
Psycho is entirely controlled with the keyboard: direction keys for moving your character around, shortcut keys for performing actions. You need to stand close to an interesting object in order to examine it. Adversaries will appear at random throughout the house, putting you to sleep by touch and thus draining your precious time -- you've only got four hours to solve the case. You may shoot the enemies as soon as you find a weapon. As there is no other option for character interaction, this is how you'll deal with the Bates family as well.