Prince of Persia

1. B (level 1, room 6; standing there doesn't make the spikes come out)
2. C (level 3, room 17)
3. D (intro; ah, Avril Harrison)

1. B. (I think the spikes' sensors can't see through wall.)
2. C.
3. D. (Avril Harrison's monogram)

Question 1: B
Question 2: C
Question 3: B (if only to complete the pattern!)

Edit:
I got 2 out of 3

1-B
2-D
3-D

4. C (level 5, room 24; if you exit the room fast enough and return, the shadow runs right)
5. A (demo level, room 6; even if you'd make the level playable and enable cheats to float there, a loose tile would drop and be on that floor)
6. A

4. D. (level 5)
5. A. (Demo level. But the only way to see this room without cheating/hacking is when the prince *falls* here, but I don't see that there.)
6. A. (I'm sure about the left pillow, but not about the right one...)

7. B
8. A
9. D (Because A is possible by exiting under the gate before the mouse arrives and then going all the way around (including drinking a potion), C is possible by opening the gate then waiting for it to close and making a running jump after returning at the last moment, and B is impossible as the mouse would push down the raise button.)

7. B.
8. A. "hail". It's hard to forget such an unusual word.
9. D. If you're fast enough, you can get out through the still-open gate before the mouse comes.
You can't jump over to the other side, but you can still go around. And then you can do A.

4: D
It can't be A, B or C, because as I remember it the button in A and the debris in B shouldn't be there, and the shadow usually doesn't run as far as shown in C.

5: C
My guess is, you played the demo level in cheat mode and pressed R after falling down into this room

6: B
It's a total guess, but I chose this one because I think that the pillows would probably have varying colors.

7: A
I would expect there to be a torch, and D is impossible because the top of the door doesn't match with the rest of the image. Then the question remains, if that window is there? I'm not sure, it might well be, but at least I don't have a clear recollection of it, so I'm going for A.

8: A
I think it was 'hail'.

9: B
B is impossible because the mouse would push down the raise button. The question then is, how would A be possible...? I cannot rule it out, because I know that if you are very fast, you can be back in that room before the gate has closed (like SuavePrince for instance recorded in his speedrun). Problem is, if you jump forward you might take damage falling down (thus, you are slowed down), which might cause the mouse to appear while you are still on that screen. But I suspect you could avoid that by jumping at the exact right moment, so you would then grab the ledge instead, then drop down safely and leave the room before the mouse appears. Then you could go back to replicate the situation in A...