>>713898891 (OP)Ace Attorney 1
It's the best because it has a unique melancholy tone that the later games (except for 2-4) don't approach again.
Despite 1-3 being a big TV studio, it feels very mundane. Colors are generally muted and nothing is larger than life. The same is true for Gourd Lake, the Gatewater, and pretty much every other element of the world we see. Compare that to the Berry Big Circus, Tres Bien, Delites House, or Vitamin Park. Things are colorful and over the top in many ways. It feels more like Scooby-Doo level caricatures than an actual world.
I also like how simple the murders were in the first game. Dude got bludgeoned, girl got bludgeoned, dude got pushed and fell onto a spike, dude got shot. The mystery is more about who killed the victim and much less about the 'how'. Meanwhile, later games all involve pretty wild scenarios (we recreated the crime in order to make it look like the victim was alone; there was a corpse pendulum; a guy dropped a bust on someone and then wheeled it up using a pulley system; etc...). Again, 2-4 is an exception where it really is just 'dude got stabbed'.
AA1 feels more grounded and there is this underlying current of how fucked the setting is. It's great.
Apollo Justice comes closest to revisiting this feeling but it also sucks as a game so I overlook it.