Some 10 years ago, or even more, I played through the DOS version (using DOSBox v0.63 or something) and covered about three quarters of the game. There are three episodes that are roughly based on the movies: first, the colony like in Aliens, then the prison from the third film, and finally, the Precursor ship.
It was not super enjoyable, and performance was not always optimal (but I guess it is better with the current DOSBox builds), but playable enough. The game certainly looks better in 16-bit colour, but it is more resource demanding than the 8-bit mode. The levels are varied enough, for the most part, but with the alien ship I got bored, not in the least because of the repetitive corridors that you have to navigate. However, the story and level progression don't make much sense from the in-universe standpoint, and in this respect Alien Trilogy is not even remotely a good Alien franchise game. What I did enjoy though was this FAQ -- back then I liked reading FAQs about games that I played.
You can try the demo version, available here.