Yeah quite a lot of aliens based mods/unofficial games got shutdown, its been awhile now (most were based on unreal tournament, quake3, half-life, etc. engines) but they are probably just as protective now.
EDIT: One I could quickly find to hand:
"In 1997 a group of folks were working on a Quake mod based on the Alien franchise simply titled Alien Quake until 20th Century Fox issued a Cease and Desist on them. The shutdown was notorious enough in the modding community to the point it even coined the term "foxed" to refer for projects similarly shut down at the request of corporations. "