Alien Isolation Special - Mousehunt in the Vent
Just for fun gameplay without flamethrower and tracker that makes you sweat like hell, and a nice skill training too. As you can see the step in the vent is one-way only for the Alien or should i say 'Sylvester' ? Without that fact it probably would not be manageable to survive a while, it's too fast and every little mistake is deadly.
PS: It's not so easy as it might look like.