I was wowed by the amount of special effects on display for something as simple as vanilla Doom 2. Despite complains about the gameplay, I found myself enjoying it for the most part; it only felt a bit wonky to have the monsters teleporting in random locations which wasn't the most ideal setup for the amount of close quarters combat you'll be having in some tighter spaces. Someone could end up not having a good time with the monster placement getting randomized while it plays nicer for others. There's some dark caves and vent tunnels, and lots of wonderful little touches throughout like animated vent fans, a plane taking off, a computer running Doom II and other detail treasures. I would liken it to a Doom museum with a gameplay gimmick that may not fancy most Doomers out there, but I quite enjoyed my time exploring the world (or moon) of Phobos. I only wish it had more maps.
I'll admit to being indecisive with how to rank this experience, despite going in expecting to take it slow with the first map opening up with no action and just letting myself get pulled into the atmosphere. The music is pretty cool and sets the mood in places - I particularly liked destroying what seemed to be some kind of device which led to the next map blaring an alarm as I scrambled around the place. It's got some nice moments that carry the action a little better but loses momentum with the frequency in maps that contain lots of halls, doors and enemies packed in a rather square-looking interior. Being a lover of old-school vanilla wads, I did have trouble committing myself by the time I reached the third map. The good points weren't enough to outweigh the negatives for me, but there's always a chance someone can appreciate what they were trying to accomplish for the time it was released.
Xenomorph Base has some cool moments and nice details to it, though I did feel in some places it either felt unpolished or wasn't as engaging as I'd hoped it would be. It's got a nice introduction to the action and starts to pick up much better with the second and third maps, however it seemed to drop in quality by that point, though I did enjoy the last map even if it felt a little shorter than expected. It does feel like something that could have used more work in places but as it stands it's an okay enough romp to blaze through.