In case it wasn't clear, Retro Knight is meant to be very silly.
Apart from just video games, there are a ton of wacky references to other things.
I've tried to list all the deliberate ones here, as well as the video game references.

There's a billion, duh. Coming soon.

Always Sunny In Philidelphia
Rum Ham - We're sorry, Rum Ham, but you're an extremely rare food in Retro Knight. Take a few tips from the legendary episode of Always Sunny on how to find it.
Aqua Teen Hunger Force
French Fries, Soda, and Meatball all are meant to look like Frylock, Shake, and Meatwad
Weinie Smoothie - The item Weinie Smoothie was made by Meatwad here, as was the line "You know how much protein is in a Weinie Smoothie?"
Flight of the Conchords
The Boom Bros. - If you know the show, you know the song. Also among the many Boom Bros, you can find Jermaine, Bret, and Rhys.
Dowie Woods - While most of this forest is about David Bowie, there are a few signs that are meant for Flight of the Conchords' David Bowie. "Wear the funky, funky eyepatch!"
Fraggle Rock
Tentee Shores - "Dance your cares away! Worries for another day! Let the music play!" Did you clap? Obviously taken from their theme song.
Kids In The Hall
Yarrrgle City - "I was just wondering about Tony at Tony's Tools: where he could be, who he is with, what is he thinking. Is he thinking of me?" I coudn't fit the whole phrase, but I got the gist.
Monty Python's Flying Circus
Mr. Dumpy - My own impersonation of Mr. Gumpy.
Angela Pimlot - A mash up of a Monty Python Pepperpot and The Simpson's Crazy Cat Lady.
Mr. Show
The Questmasters - "Questmaster hey! Questmaster hoe! Questmaster Questmaster go go go!" is very similar to what America's founding fathers used to say. Interesting.
Mystery Science Theater 3000
Turkey Day - During Turkey Days, you can find Film Reels and deliver them to Dr. Kockpocalipse. He claims he is NOT using them to torture a man in space. Has Dr. Kock taken an idea from Dr. Forrester?
The Simpsons
Angela Pimlot - A mash up of a Monty Python Pepperpot and The Simpson's Crazy Cat Lady.
Star Trek: The Next Generation
The Nostalgia Queen - She sells a Trek Suit that looks familiar.
Teenage Mutant Ninja Turtles
The Nostalgia Queen - She sells a Turtle Suit that looks familiar.

Avengers: Infinity War
Storm Ripper Axe - Taken from the Stormbreaker Axe which seems to take up almost half of this movie.
Protein Bar - Jester mentions that it is "Good for bones."
The Nostalgia Queen - She sells a Merc Suit that looks familiar.
The Nostalgia Queen - She sells a Buster Suit that looks familiar.
Happy Gilmore
Scooter McGavin - The owner of the Scooter Shop has an interesting name.
Jurassic Park
Isla Malidea - Sorry to spoil things, but I guess there's an island off of Kingdomland where a previous king tried to make his own amusement park. It didn't go well.
Twilight Forest - Dowie Woods is full of David Bowie lyrics and Labrynth references.
Lego Batman
Bat Suit - While one could say it is just Batman, I modeled it after Will Arrent's amazing character.
Monty Python and The Holy Grail
The Questmasters - These wierdos are meant to look like The Knights of Ni. Some even say "Ekki-Ekki-Ekki-Ekki-P'tang! Zoom-Boing! Z'nourrwringmm!"
Cayerbanogg Cave - It's supposed to have a scary bunny in front of it. Spelling has been changed.
Something About Mary
Gordon Village - "Who's been to Santiago, Chile twice in one year!?" Someone answer that.
Star Wars
The Nostalgia Queen - She sells a Storm Suit that looks familiar.
The Nostalgia Queen - She sells a Cyber Suit that looks familiar.

The Aquabats
The Nostalgia Queen - She sells a Aqua Suit that looks familiar.
David Bowie
Twilight Forest - Dowie Woods is full of David Bowie lyrics and Labrynth references.
Less Than Jake
Rockview - Named after their legendary album "Hello Rockview".
Neil Young
Rockview - "Keep on rockin' in the free world, or as free as the king allows it." I think this one is pretty obvious.
Cherry Pie - Even I won't make the obvious reference here. You know what it is.
Lionel Richie
The Holiday Master - During Fiesta days, The Holiday Master sings a bit of "All Night Long".

Eddie Izzard
Ciaofiasco City - "I just love riding my little scooter all over town! Ciao!" While 'Ciao' is obviously a common phrase, I meant to reference this clip. Of course, I had to add a scooter powerup so you can reinact it.
Paul F. Tompkins
The King Hat - He really hates it when you call a Crown a King Hat. The whole clip is great.
George Foreman
Builder Brigade - Their leader is Foreman George.