Xen was pretty terrible in the original. I always loved the middle act of the game, basically from We've Got Hostiles onward until going through the teleporter, but that's usually where I stopped playing. The really alien, slightly demonic aesthetic didn't really appeal to me. Or the headcrabs...
My real favorite was Opposing Force. It's unfortunate that games have become so complicated and mod-unfriendly that that font of creativity has pretty much dried up. I'm amazed at Black Mesa, but back in the early 2000s, you didn't need a large team to make decent levels, or even total conversions.
My real favorite was Opposing Force. It's unfortunate that games have become so complicated and mod-unfriendly that that font of creativity has pretty much dried up. I'm amazed at Black Mesa, but back in the early 2000s, you didn't need a large team to make decent levels, or even total conversions.