Visual Novel: The Portopia Serial Murder Case

The Portopia Serial Murder Case (ポートピア連続殺人事件 ) is the Trope Maker for Visual Novels, created by Yuji Horii (who then went on to create console RPG trope maker Dragon Quest). Originally for the NEC PC-6001 computer in 1983 and ported to the Famicom console (with improvements) in 1985.

Here's the Wikipedia page.

Tropes found in this game include:

  • Asshole Victim: You eventually discover that the victim was responsible for some extremely unsavory things.
  • Book Safe: There's a key found in a book in the mansion.
  • Chalk Outline: As shown on the box artwork, and in-game. It's simply used to show where the body was located.
  • Detective Mole: Sort of. As in, your assistant is the killer.
  • Pixel Hunt: There are four items you need to find to progress with the game. Of these, at least two aren't linked with an obvious visual cue.
  • Police Brutality: Values Dissonance for many modern players; the interface has an actual 'hit' button, which (among other things) you must use on suspects during interrogations in order to proceed.
  • Police Procedural: While not remotely accurate (you freely use brutality in interrogations, for instance), the game focuses a lot more on this aspect of play than many later entries in the genre.
  • Revenge: The killer's motive.
  • Shout-Out: The maze you explore at the end is a shout-out to Wizardry; in particular, at one point there's an inscription on the wall saying that a monster leaps out at you (it doesn't.)
  • Unexpected Genre Change: At one point, the game unexpectedly shifts from a pixel-hunting detective mystery to a 3D-ish Wizardry-style maze explorer (though with no RPG mechanics.) This is because Yuji Horii actually created the game after being impressed by Wizardry itself at a demonstration in the US; his ultimate goal was just to make enough money to fund what would eventually be Dragon Quest.