1, 3, 5, 6 are correct.
9 is correct so far; just need the character name.
15, 19 are correct.
20 is incorrect (Corman only distributed it).
 

I just doublechecked and one of the TMNT games apparently has a song called Sewer Surfin'. But as far as I can tell, for the movie I'm thinking of, there's the "g" in the name.

20 is correct.

7. Han Solo, Empire Strikes Back?

Remaining answers:

2. Who was the headliner sponsor for [Sponsor] Presents: The Greatest Movie Ever Sold?
Pom Wonderful

4. Farts of Darkness is the documentary of the making of which movie?
Terror Firmer

8. What was the sequel to House of 1,000 Corpses?
The Devil's Rejects

10. Which band performed the opening theme for Casino Royale (1967)?
Herb Albert & the Tijuana Brass

11. Which character in which superhero movie declared, "Bomb! Bomb! Bomb!"
Bane, Batman and Robin, aptly describing the movie

13. In Troma's War, which character was a veteran soldier and what was his occupation at the time of the movie?
Parker; used car dealer

14. In which movie can you find the song Sewer Surfing?
Joe's Apartment



18. What song plays at the closing credits of Serial Mom?
Daybreak

Andy E. Nystrom wrote:

5. In which movie did Meg Ryan play three different characters?
6. Jean-Claude Van Damme played himself in this self-reflecting movie.
10. What is the other common name for Hercules Goes Bananas and who played Hercules?
11. Who played the titular role in the 2009 version of Willard?
12. What was the name of the Hitler-like character in The Great Dictator and who played him?
13. This western's cast was entirely little people.
15. Which character from The Incredible Hulk has been confirmed as returning in Shang-Chi?

5. Joe vs. the Volcano?
6. JCVD
10. Hercules in New York, Arnold
11. Crispin Glover?
12. Charlie Chaplin
13. The Terror of Tiny Town
15. Abomination

12 Adenoid Hynkel
14 Godzilla Raids Again
17 From Dusk Till Dawn 2: Texas Blood Money; From Dusk Till Dawn 3: The Hangman's Daughter
19 Tootsie

Calling a day on the following:
1. What was the name of Citizen Toxie's Making Of documentary?
2. What was the name of From Dusk Till Dawn's Making Of documentary?
3. Who did Brick Bronsky play in Class of Nuke 'Em High 2 & 3?
4. Who did Brick Bronsky play in Sgt. Kabukiman NYPD?
7. Who played the titular character in Andre the Butcher?
8. What was the third movie in the Feast series?
9. Who did Sid Haig play in House of 1,000 Corpses?
16. Who did Dana Delany voice in Batman: Mask of the Phantasm?
18. What was the name of the first movie that Robin Williams appeared in?
20. Who played the main character in The Warrior and the Sorceress?

1. This low budget movie was "inspired by" the then recent Abraham Lincoln, Vampire Hunter movie
2. This low budget movie was "inspired by" the then recent Thor movie
3. This oversized book was full of photos and interviews with numerous cast and crew members of the various Friday the 13th movies to that time.
4. What song did a few crew members sing at the start of Star Trek V?
5. Which character from Batman 1989 returned for the the Arrowverse Crisis on Infinite Earths event?
6. Who were the two writers on Tromeo & Juliet?
7. Monster was based on which real life person (and who played them)?
8. Roddy Piper starred in this alien invasion movie.
9. Jesse Ventura played an alien hero in which movie?
10. Who were the two main villains in From Russia with Love?
11. In A Clockwork Orange, what does Alex sing while committing rape?
12. Which song gets spoofed in a dream sequence in UHF?
13. In Plan 9 from Outer Space, which actor, after passing away, was replaced by someone else holding a cape over their face in their scenes?
14. In Slumber Party Massacre, what was the "code name" of the killer?
15. Which movie's artistic merits were initially largely overlooked by the public because it had an actress from a wholesome sitcom (still airing at the time) appear nude in the movie? And which actress and sitcom?
16. In Airplane II: The Sequel, who appears just in the "little breather" gag?
17. What movie was about a woman's most intimate body part gaining the ability to think and speak?
18. Who played the judge in Stuck on You! (1982)?
19. Who played Larry in Dirty Larry, Crazy Mary?
20. Can I Do It Till I Need Glasses? (Robin Williams' first movie from the previous quiz) was a sequel of sorts to which movie?

Those are all correct.

6 is incorrect.
7 is close enough:surname for the former is Wuornos
11 and 15 are correct. Angel Heart has gained more of a following in recent years as, after the controversy subsided, people started to realize it's actually a pretty good movie.
20 is incorrect.
 

20 is still incorrect. Hint: Can I Do It Till I Need Glasses?'s title can be seen as a question responding to the earlier movie's title.

Remaining answers:

1. This low budget movie was "inspired by" the then recent Abraham Lincoln, Vampire Hunter movie
Abraham Lincoln, Zombie Slayer

2. This low budget movie was "inspired by" the then recent Thor movie
The Almighty Thor

3. This oversized book was full of photos and interviews with numerous cast and crew members of the various Friday the 13th movies to that time.
Crystal Lake Memories

5. Which character from Batman 1989 returned for the the Arrowverse Crisis on Infinite Earths event?
Alexander Knox

6. Who were the two writers on Tromeo & Juliet?
James Gunn and Lloyd Kaufman. James Gunn of course disappeared from the public eye after this and was never heard from again.

9. Jesse Ventura played an alien hero in which movie?
Abraxas, Guardian or the Universe

12. Which song gets spoofed in a dream sequence in UHF?
Money for Nothing (MTV theme)

14. In Slumber Party Massacre, what was the "code name" of the killer?
The Driller Killer

16. In Airplane II: The Sequel, who appears just in the "little breather" gag?
Hervé Villechaize

17. What movie was about a woman's most intimate body part gaining the ability to think and speak?
Chatterbox

18. Who played the judge in Stuck on You! (1982)?
Professor Irwin Corey, who lived to 102

19. Who played Larry in Dirty Larry, Crazy Mary?
Peter Fonda

20. Can I Do It Till I Need Glasses? (Robin Williams' first movie from the previous quiz) was a sequel of sorts to which movie?
If You Do It, You'lL Go Blind

Andy E. Nystrom wrote:

1. Oscar, The Wrestler, Unhook the Stars
2. Friday the 13th, Super, Flatliners
3. The Hot Spot, The Hulk, A Beautiful Mind
6. Shrek 2, Die Another Day, The Adventures of Pluto Nash
7. Dead Man Walking, Bull Durham, Pretty Baby
8. Short Cuts, Magnolia, Boogie Nights
9. Tropic Thunder, Collateral, Eyes Wide Shut
12. Chopper Chicks in Zombietown; Monster's Ball; A Gun, a Car, a Blonde
13. Private Parts, Sideways, American Splendor
15. Heavy Metal, Going Berserk, Spaceballs
16. Sister, Sister; The Anniversary Party; Flesh+Blood
18. Marty, The Dirty Dozen, REDS
19. Wrong is Right, The Anderson Tapes, DragonHeart
20. The Return of the Living Dead, Night of the Demons, Still Smokin

1. Marisa Tomei?
2. Kevin Bacon?
3. Jennifer Connelly
6. Halle Barrie?
7. Susan Sarandon
8. Julianne Moore
9. Tom Cruise?
12. Billy Bob Thornton?
13. Paul Giammatti
15. John Candy?
16. Jennifer Jason Leigh?
18. Ernest Borgnine?
19. Sean Connery?
20. Cheech Marin?

20. Tommy Chong?