-Do you like or dislike this Pokémon? Why?
Love it. Don't quite know why, there's plenty of reasons.
-How is this Pokémon in-game?
The trade evolution aspect from Haunter could understandably be annoying if you have nobody to trade with, but I'd call Gengar a good payoff.
-How is this Pokémon in competitive play? Are there any interesting strategies you like to use for them?
It's still the only Pokémon to have been OU in Smogon's tiers since Gen I, that alone shows how consistently good Gengar is.
Three attacks (Shadow Ball, Sludge Bomb/Wave, Focus Blast) and something to work around Sucker Punch (Destiny Bond, Disable, Substitute, Reflect Type, even Torment if I'm feeling ballsy). For the Mega, there's Perish Trapping. When it isn't Mega, I most often use Mega Houndoom for a dance partner. Whenever I want some more out of the box options, there's Hex, Dazzling Gleam, and Icy Wind. There's one reason I like it, the versatility is awesome.
-Do you like this Pokémon's representation in the anime? Are there any moments or qualities in particular you enjoy/dislike?
I'll admit to enjoying the sight of Agatha's Gengar beating Ash's Pikachu, and that first PMD special did well to show Gengar of Team Meanies being a jerk (why they didn't follow this up with using Team Skull's trio in the next special is beyond me) but I might possibly remember Jarvis's Gengar most despite not seeing the full movie yet because it's Shiny (I like Shiny Gengar even more) and owned by the movie's antagonist.
-How do you think this Pokémon would interact with our world?
Malicious trickster, but I can't picture them being an outright threat to life as we know it. Those in warmer locations might like its heat stealing capabilities.
-If given the power to, would you change anything about this Pokémon and if so, what would you change?
The only definite one would be to give it access to Sludge Wave from the move's TM for once instead of making it event exclusive. I could also give it Calm Mind, Nasty Plot, Psyshock, and Aura Sphere, but that's verging into wishlist territory.
-Do you yourself have any other theories for what went into this Pokémon’s design?
Not really, but I theorise that Gengar may be a cold blooded creature. That would explain why it steals the warmth from its surroundings. I also got an uproarious laugh out of this. Don't worry about the math, just think of the implications.
-As the first of its type do you think this Pokémon did a good job laying the groundwork?
Yeah, definitely. Gengar showed us the Ghost type's preference towards special attacks and speed. Later Pokémon of that type would break the mold (Dusknoir and Golurk families come to mind) but Gengar's stat spread is still what I imagine when thinking about the Ghost type.
-As the only one of it’s type for years how do you think this Pokémon fared?
As the only one of it's type for years, it was also the only Pokémon immune to Body Slam and Hyper Beam for years, a massive deal in competitive Gen I. I'm almost convinced that having Levitate at this time would have gotten Gengar the same treatment its Mega Evolution gets today. Then again, there's that one anomaly with a certain type...
-What are your thoughts about the fact that this Pokémon was once the only one of its type?
It was quite interesting. Outside of the Normal and Fighting immunities, the Ghost type didn't have much to speak of initially despite nothing resisting it. Lick was painfully weak and Psychic was without a doubt erroneously immune to Ghost at the time. Despite these flaws, Gengar's still held up for 20 years and counting.
