It is actually a different puzzle - click Begin Puzzle on it and you'll see. @JeffPrug came up with this neat trick of using a second puzzle as the meta submission mechanism until Crosshare adds support for that.
Glad you enjoyed it! Thanks to Mike D for already explaining, but sorry that the links just kept bouncing you back and forth, I hopefully clarified the instructions on the answer puzzle.
What can quickly happen after a volcanic eruption?
21A
Cincinnati team
22A
She's 16 going on 17, in a "Sound of Music" song
23A
Acorn producer (or surname of a professor)
24A
Better for catching flies than vinegar
25A
Animal docs
26A
Credit card stat.
27A
Whisper sweet nothings
29A
Savings plan with a $6000 yearly contribution limit
30A
J.J. Abrams special effect for Alias, but not Star Wars?
37A
Home of the Braves
39A
Nicknames of Jared Lorenzen (R.I.P.) include The Hefty Lefty, The Pillsbury Throwboy, The Round Mound of Touchdown, and He __ Me
40A
NYC area above Houston Street
41A
College near 37A
42A
Any non-zero number to the power of zero
43A
Samwise suggested sticking potatoes in a this
44A
Confusingly, can describe either immigrants or their children. Many nostalgic gamers prefer this entry of a series
50A
Prefix meaning "pressure"
51A
One of the denizens of NIMH who helped Mrs. Frisby
52A
Massachusetts' Cape ___
53A
Smell
54A
Female sibling, for short
55A
"Good point, bro"
59A
Warrior Princess, who domesticated a small horse?
63A
Nod follower
64A
Sum up
65A
"Who ___ to judge?"
66A
End for digest or convert
67A
Archaeologist's find
71A
Simon & Garfunkel, for example
72A
PlayStation game __ Bandicoot
74A
Baking appliance
75A
A crab who puts off shedding its shell?
79A
Pipe problem
80A
McCovey __ at Giants' Stadium, where many a home run has splashed
81A
Those consuming lollipops
82A
Finishes
83A
"Wheel of Fortune" turn
84A
Those fancy letters we all drew in elementary school
Verticales
1D
"___ favor, señor"
2D
Ready to spring into action
3D
Karl Marx's Das ___
4D
Actresses Falco and McClurg
5D
Mikkelsen of TV's "Hannibal"
6D
Face-to-face exam
7D
'80s video-game console
8D
Dog's double talk
9D
Linger in the tub
10D
Down with the sickness
11D
Everyone
12D
Main character
13D
Oregon Trail purchases to pull your wagon
14D
Fries or rice
15D
Online crafts site
20D
A basketball player who can jump high is said to have these
24D
Ken Jennings was not given credit for this answer as a long-handled gardening tool that also means "Immoral Pleasure Seeker" (it was supposed to be "rake")
25D
By way of
26D
Scoreboard shorthand for Ducks (and formerly Angels)
27D
Provide food for a large gathering
28D
You can dig it
30D
Course code for a college class about the study of language
31D
Coup d'___
32D
LaVar Ball told reporter Kristine Leahy to stay in her __
33D
Younghoe Koo had two successful kicks of this type in one game (and a third called back due to penalty)
34D
DARE motto: "Just say ___ drugs"
35D
"That was ___, this is now"
36D
It could be of one of chastity
38D
Seymour Skinner claimed that the borealis version of this was localized entirely within his kitchen
42D
Can. province which contains Toronto
44D
Disappear slowly
45D
Wood alternative
46D
Repeatedly fight in a video game in order to gain experience
47D
Difficulty setting
48D
Farm measurement traditionally defined as 66 by 660 feet
49D
Travel with a band
50D
Take on Tyson
54D
Lay down the lawn
55D
Texter's response to oversharing
56D
Electronic music genre with prominent sub-bass
57D
Fully accounted for
58D
Children's version of baseball
60D
___-12 Conference
61D
Stretch tight
62D
Spanish love
66D
'May __ favor?'
67D
Part in a play
68D
A multiple of 2
69D
Its symbol is Pb
70D
Signs
71D
556, to Caesar
72D
TV shows with varieties that include Miami and New York