Amazing re-imagining of the themes from Half Life. Each track brings a refreshing new take on each chapter's atmosphere. I especially loved the more intense tracks used when engaging in the more chaotic battles, like Surface Tension 1.
Dziban F4-1M is amazing. Starts out as industrial/electronic, then escalates into hard rock with an epic electric-guitar crescendo. A high-octane track that matches the action of the game.
Amazing soundtrack that matches the action and intensity of the game. I especially love "Enjoy the Silence", since it reflects the brief calm before a spectacular showdown full of explosive energy and destruction.