#24, SNOBOL4 (CSNOBOL4), 256 bytes

.;*->+|a	"x"	a|+>-*;.
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input;* Henry Jams?
	X =INPUT
	OUTPUT =GT(SIZE(X),21)	1
	
	
	
	
	
	
	
	
	
	
	
	
	
end	
	ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234
	Hi, Retina!
	~

Try it online!

Prints out 1 for truthy and outputs nothing for falsey.

Satisfies:

2. The first character is a ..
3. It contains an e.
4. Its length is even.
5. Its length is a perfect square.
6. It contains an a.
7. It contains a > character.
8. Contains the exact string ->.
9. Contains the exact string Hi, Retina!.
10. The sum of the first two Unicode code points is a multiple of 5.
11. The 10-th character is a ".
12. The last non-empty line does not have any duplicate characters.
13. The first line is a palindrome of length > 5.
14. The first line is exactly 21 characters long (not including newline).
15. It contains a ?.
16. It contains a |.
17. Contains a +.
18. It is at least 28 lines long.
19. The following characters are used five times in total: !"#$.[\] and the codepoint of the second character is less than 60.
20. Contains Henry Jams? as a continuous substring.
21. The last character is ~.
22. It contains a C
23. Each line contains a tab character.
24. The ninth line contains at least 22 characters, excluding the newline.

For future answers:

• The first character is a ., and so is the 21st character (palindromic rule).
• The 10th character is a ", and so is the 12th character (palindromic rule).
• The first line is a palindrome of length 21.
• The second character's Unicode code point, mod 5, is 4, and its code point is lower than 60 (the printables are ',1;6 and tab).
• The last character is ~.
• Its length is an even perfect square.
• It is at least 28 lines long.
• The ninth line must have at least 22 characters, excluding the newline.
• The last non-empty line does not have any duplicate characters.
• Contains the exact strings ->, Hi, Retina!, and Henry Jams?.
• It contains |, + and C.
• Each line contains a tab character.
• Each program is now allowed only the 2 . and 2 " in the first line, and the ! in Hi, Retina!. Those characters cannot be used anywhere else, in addition to no uses of #$[\].

24, SNOBOL4 (CSNOBOL4), 256 bytes

.;*->+|a	"x"	a|+>-*;.
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input;* Henry Jams?
	X =INPUT
	OUTPUT =GT(SIZE(X),21)	1
	
	
	
	
	
	
	
	
	
	
	
	
	
end	
	ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234
	Hi, Retina!
	~

Try it online!

Prints out 1 for truthy and outputs nothing for falsey.

Satisfies:

2. The first character is a ..
3. It contains an e.
4. Its length is even.
5. Its length is a perfect square.
6. It contains an a.
7. It contains a > character.
8. Contains the exact string ->.
9. Contains the exact string Hi, Retina!.
10. The sum of the first two Unicode code points is a multiple of 5.
11. The 10-th character is a ".
12. The last non-empty line does not have any duplicate characters.
13. The first line is a palindrome of length > 5.
14. The first line is exactly 21 characters long (not including newline).
15. It contains a ?.
16. It contains a |.
17. Contains a +.
18. It is at least 28 lines long.
19. The following characters are used five times in total: !"#$.[\] and the codepoint of the second character is less than 60.
20. Contains Henry Jams? as a continuous substring.
21. The last character is ~.
22. It contains a C
23. Each line contains a tab character.
24. The ninth line contains at least 22 characters, excluding the newline.

For future answers:

• The first character is a ., and so is the 21st character (palindromic rule).
• The 10th character is a ", and so is the 12th character (palindromic rule).
• The first line is a palindrome of length 21.
• The second character's Unicode code point, mod 5, is 4, and its code point is lower than 60 (the printables are ',1;6 and tab).
• The last character is ~.
• Its length is an even perfect square.
• It is at least 28 lines long.
• The ninth line must have at least 22 characters, excluding the newline.
• The last non-empty line does not have any duplicate characters.
• Contains the exact strings ->, Hi, Retina!, and Henry Jams?.
• It contains |, + and C.
• Each line contains a tab character.
• Each program is now allowed only the 2 . and 2 " in the first line, and the ! in Hi, Retina!. Those characters cannot be used anywhere else, in addition to no uses of #$[\].

SNOBOL4 (CSNOBOL4), 256 bytes

.;*->+|a	"x"	a|+>-*;.
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input;* Henry Jams?
	X =INPUT
	OUTPUT =GT(SIZE(X),21)	1
	
	
	
	
	
	
	
	
	
	
	
	
	
end	
	ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234
	Hi, Retina!
	~

Try it online!

Prints out 1 for truthy and outputs nothing for falsey.

Satisfies:

2. The first character is a ..
3. It contains an e.
4. Its length is even.
5. Its length is a perfect square.
6. It contains an a.
7. It contains a > character.
8. Contains the exact string ->.
9. Contains the exact string Hi, Retina!.
10. The sum of the first two Unicode code points is a multiple of 5.
11. The 10-th character is a ".
12. The last non-empty line does not have any duplicate characters.
13. The first line is a palindrome of length > 5.
14. The first line is exactly 21 characters long (not including newline).
15. It contains a ?.
16. It contains a |.
17. Contains a +.
18. It is at least 28 lines long.
19. The following characters are used five times in total: !"#$.[\] and the codepoint of the second character is less than 60.
20. Contains Henry Jams? as a continuous substring.
21. The last character is ~.
22. It contains a C
23. Each line contains a tab character.
24. The ninth line contains at least 22 characters, excluding the newline.

For future answers:

• The first character is a ., and so is the 21st character (palindromic rule).
• The 10th character is a ", and so is the 12th character (palindromic rule).
• The first line is a palindrome of length 21.
• The second character's Unicode code point, mod 5, is 4, and its code point is lower than 60 (the printables are ',1;6 and tab).
• The last character is ~.
• Its length is an even perfect square.
• It is at least 28 lines long.
• The ninth line must have at least 22 characters, excluding the newline.
• The last non-empty line does not have any duplicate characters.
• Contains the exact strings ->, Hi, Retina!, and Henry Jams?.
• It contains |, + and C.
• Each line contains a tab character.
• Each program is now allowed only the 2 . and 2 " in the first line, and the ! in Hi, Retina!. Those characters cannot be used anywhere else, in addition to no uses of #$[\].

#24, SNOBOL4 (CSNOBOL4), 256 bytes

.;*->+|a	"x"	a|+>-*;.
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input;* Henry Jams?
	X =INPUT
	OUTPUT =GT(SIZE(X),21)	1
	
	
	
	
	
	
	
	
	
	
	
	
	
end	
	ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234
	Hi, Retina!
	~

Try it online!

Prints out 1 for truthy and outputs nothing for falsey.

Satisfies:

2. The first character is a ..
3. It contains an e.
4. Its length is even.
5. Its length is a perfect square.
6. It contains an a.
7. It contains a > character.
8. Contains the exact string ->.
9. Contains the exact string Hi, Retina!.
10. The sum of the first two Unicode code points is a multiple of 5.
11. The 10-th character is a ".
12. The last non-empty line does not have any duplicate characters.
13. The first line is a palindrome of length > 5.
14. The first line is exactly 21 characters long (not including newline).
15. It contains a ?.
16. It contains a |.
17. Contains a +.
18. It is at least 28 lines long.
19. The following characters are used five times in total: !"#$.[\] and the codepoint of the second character is less than 60.
20. Contains Henry Jams? as a continuous substring.
21. The last character is ~.
22. It contains a C
23. Each line contains a tab character.
24. The ninth line contains at least 22 characters, excluding the newline.

For future answers:

• The first character is a ., and so is the 21st character (palindromic rule).
• The 10th character is a ", and so is the 12th character (palindromic rule).
• The first line is a palindrome of length 21.
• The second character's Unicode code point, mod 5, is 4, and its code point is lower than 60 (the printables are ',1;6 and tab).
• The last character is ~.
• Its length is an even perfect square.
• It is at least 28 lines long.
• The ninth line must have at least 22 characters, excluding the newline.
• The last non-empty line does not have any duplicate characters.
• Contains the exact strings ->, Hi, Retina!, and Henry Jams?.
• It contains |, + and C.
• Each line contains a tab character.
• Each program is now allowed only the 2 . and 2 " in the first line, and the ! in Hi, Retina!. Those characters cannot be used anywhere else, in addition to no uses of #$[\].

#24, SNOBOL4 (CSNOBOL4), 196 bytes

New requirement: the ninth line must contain at least 22 characters, excluding the newline.

.;*->+|C	"x"	C|+>-*;.
	INPUT
	INPUT
	INPUT
	INPUT
	INPUT
	INPUT
	INPUT
	INPUT;* 1 Henry Jams?
	X =INPUT
	OUTPUT =GT(SIZE(X),21)	1
	     
	     
	   
	     
	
	
	
	
	
	
	
	
	
end	
	
	Hi, Retina!
	~

Try it online!

SNOBOL4 (CSNOBOL4), 256 bytes

.;*->+|a	"x"	a|+>-*;.
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input
	x =input;* Henry Jams?
	X =INPUT
	OUTPUT =GT(SIZE(X),21)	1
	
	
	
	
	
	
	
	
	
	
	
	
	
end	
	ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234
	Hi, Retina!
	~

Try it online!