It's funny you mention only armor piercing rounds damaging it. Dan O'Bannon, the late original writer that came up with Alien, insisted on not having the typical "bullets won't kill it!" cliché. He wanted the monster to be just like any other animal in that if you shoot it, it will die. The acid blood was made up by Ron Cobb, one of the artists, to counter the option of the crew to simply shoot the thing.
Then again, the space jockey was originally an alien that looked nothing like humans, and here we are...people will change things all the time.
Other alien games may have them as tough as wet paper, but Isolation made them too tough. I think Alien Resurrection on PS1 was a great mix of tension and still being able to kill them, even if it was too hard.