It's definitely a good film. It's most certainly one of the best action films ever made. But can it truly compare to the original film? Regrettably, not so much...

It begins strongly enough, building upon the strengths of the original and carrying on immediately after it. It keeps the great protagonist of Ripley and continues her story while expanding the concept of an ensemble cast, once again filling it with unique and differing characters (even essentially causing the "evil corporate figurehead" to become an archetype in it's wake), all developing more than two dimensions over the course of the movie. The first thirty minutes is a nice slow burn as well, with information about LV-426 slowly being trickled to both Ripley and the audience before we are finally transported there alongside the Space Marines. James Cameron constructs some amazing action scenes that happen every ten minutes from this point, and since the movie took it's time to develop it's characters you're genuinely on the edge of your seat the whole as to what will happen to them next. The child character of Newt becoming one of the key narrative elements has to be one of the most unexpected parts to have ever appeared within an action movie. Not to mention that awesome final encounter with a certain "bitch", as Ripley puts it.

But it's so vastly different from the original Alien that it's... Jarring when you begin to watch it. The franchise goes from being a cerebral sci-fi horror film to a large-scale action movie, and this becomes extremely difficult to adjust to, especially considering what a masterpiece the original film is. And because of how great the original was you begin to constantly compare Aliens to the original film, yet because they are such different beasts there is obviously no comparison. You become preoccupied with comparing rather than enjoying. And as a result, you begin to enjoy it less.

Yet if you can take both films on as separate movies that are not linked in any way, then you might enjoy it. One is a great sci-fi horror, while the other is a great sci-fi action. But if you cannot separate the two, like this reviewer cannot... Expect to not enjoy it as much as you should.