Answers are below (how surprising)
1: C
2: D
3: A
4: D
5: As long as you don't feel like doing a sequence break (which will glitch the game anyway), C
6: Don't know, but I died there once in No Death Mode. Don't ask...
7:
and 
8: I'm assuming you're still talking about the Space Station? Green Grotto then.
9: 20
10: The room with the teleporter
11:
12: and 
13:
14: Can't remember
15: (I think?)
16: That he was unsure about if they ever would be able to escape the polar dimension
17: The antenna
18: doomS and Swoop
19: COMBINE! *merge into a giant version of the characters* (is it called VVVVVVman? At least it is in the scripting - vvvvvvman()) *wreaking havoc* *undo the merge*
20: "about 10 seconds"
1: C
2: D
3: A
4: D
5: As long as you don't feel like doing a sequence break (which will glitch the game anyway), C
6: Don't know, but I died there once in No Death Mode. Don't ask...
7:
and 8: I'm assuming you're still talking about the Space Station? Green Grotto then.
9: 20
10: The room with the teleporter
11:
12:
and 13:
14: Can't remember
15:
(I think?)16: That he was unsure about if they ever would be able to escape the polar dimension
17: The antenna
18: doomS and Swoop
19: COMBINE! *merge into a giant version of the characters* (is it called VVVVVVman? At least it is in the scripting - vvvvvvman()) *wreaking havoc* *undo the merge*
20: "about 10 seconds"