AVPClassic is a good game though I only played the gold version, personally I prefer the sequel by monolith for the reasons a member stated above, better narrative and I enjoyed playing as an alien in it as you went through the whole lifecycle and felt like an alien, I love the sound effects as well, right from the movies (predator vision and lock-on) for example.
That being said, everyone has different tastes and if you didn't like it, you didn't like it, I don't remember the Aliens being lightning fast in it though, I killed them all fairly easy far as I remember, it may simply down to either experience and reaction time. If you are slow to react then you will get killed. Try practicing or change the sensitivity settings.