Minerva: Metastasis is a very well done mod that plays out in the HalfLife2 universe. The map is a bit like Silent Cartographer in Halo — an island with a secret base in the middle. Also a snarky god-like voice pops in during the game to offer enigmatic hints. I really enjoyed it – it builds up tension and has some nice set-pieces along the way. It has some great music at key moments, and the quality of the map is really great.
It’s a nice example of how a little can go a long way. A headcrab is scary when it pops out at you in a tight corridor. A few dozen headcrabs are scary if you are stuck in a lift with them (think of the huge lift at the beginning of HL1) — but this mod plays it quiet. A deserted warehouse is creepy. A deserted warehouse with a dead headcrab in it and an unknown number of live ones is terrifying — even if the actual number of live headcrabs turns out to be one.
Most of the action is focused on combine forces, not zombies or headcrabs, so you get a nice variety of tactics to fight against. The AI is good enough to give rise to those emergent little moments of genius. Towards the end a few bucketloads of soldiers land and start tromping through the base. The multitude of corridors means that the direction of attack isn’t certain. I ended up in a dark little room off to one side, and watched in amazement as a platoon jogged right past me, heading for their destination. As long as I didn’t draw attention to myself, they carried on. They weren’t psychic. They didn’t turn and attack for no reason. A sweet little moment.
Anyway – go and download it — you’ll need to restart STEAM in order for it to pick up the new module after you’ve installed it.