Correct
Cannot be unseen ;_;
Jesus Christ, S. That is the single most beautiful drawing, ever.

c2a5b
c2a5b
correct

c4a3? Looks like the bottom of that tall green room that Nihilanth can teleport you to.
Nope. Easier version:

c4a2b, upside down view from the ceiling after exiting the tunnel
I don’t think there are any more Xen trees like that throughout the game, only in Gonarch maps.
Right! ½ points for requiring the easy version.
Guess the map by triggers? The colours are the default ones from Bunnymod Pro trigger display, triggers that you can’t display with the said trigger display (no such cvars) are white. Please ignore a hurt trigger being so wide, it should be pretty narrow.

You should give money rewards for guessing that shit right ._.
^
Nice replacement for a nonexistent [spoiler]

[size=8pt]^ wow…
I’d guess the first map of We’ve got hostiles
Nope. Try harder.