Better then HL2 and EP1. the only thing keeping this review from a 10 is length.
Graphics: (8/10) When HL2 came out in 2004, the graphics were cutting edge. 3 years later, the graphics were starting to ware thin. A little later that year, COD4 blew everyone's mid with graphics. I'm just saying, let's hope for a new engine for EP3 or HL3 (whichever one comes first)
Sound: (8/10) Again, impressive for the time, but doesn't hold up so much later.
Voice Acting: (10/10) The voice actors did an amazing job selling these characters. Even extras such as rebellions did an amazing thing in EP2.
Gameplay: (9.5/10) Same old amazing formula. Leaving it alone is a good thing. You don't want them to screw it up)
AI: (10/10) Some of the best AI around.
Recommendation: HL fans: 10. Other: 9.