For those of you who don't know spanish, I will make this little comment to talk about the map.
Excellent map series with nice architecture, custom enemies (from sweet half life and point of view) and a nonsensical story, driven by objective/missions during different stages of defending certain locations, that sometimes change as players advance. A few other maps have an object hunt and boss battle type of gameplay, also while defending with the aid of several NPCs which tones down difficulty a bit if you make some side missions to summon allies or activate powerful weapons.
Maps:
A1 - Disconnected from the other maps, this is set in Black Mesa. Players have to advance, find and destroy a super weaponized tank. Xonxt the friendly vort from point of view is there to help. The aliens may attack as well with their own ship, and oh boy it is nice to see.
B, C, D - In these maps the players are on Xen, where parts of Black Mesa were teleported, or perhaps all of it was already built there, mixing both human and alien architecture. Players must advance through the facilities while defending different points as they advance and gather crystals to power up teleporters and a train to escape. In maps C and D you can choose the allies that will help you between Black Mesa personell or the SPF from point of view. The sequel to these (portal house E) is on the works as far as I know.