a demo version of hl2 is out now. i downloaded it last night and played it for about 15 minutes before going to bed. i was amazed at the graphics and the physics of the game. the textures and the lighting makes "city 17" feel very real. it feels like what i would imagine some forgotten, god-forsaken town in communist russia would look like on an autumn evening. the atmosphere is just fantastic and there is a shred of storyline to go with it.
i played it for about 3 more hours just now. the first part of the demo is all exploring and watching while the second half is all shooting and puzzles. i think the bulk of the game is shooting and puzzles and i was disappointed by this. it started to feel like doom 3. i continued to explore and shoot and find levels and hidden hallways to progress.
overall it was great fun to see first hand the best of the current gaming engines. maybe a future game will be able to have the same atmosphere with more storyline.