So it's not too bad, in fact, it's remarkably well re-fined, the action is intense and relentless with no time to breath except between battles. I played it sporadically over 3 days and it kept my attention all the way through.
Who cares about the dated HL2 engine?! Gameplay gameplay gameplay is all that matters. I found myself making use of the physics engine much more than I did in HL2, and physics just seemed to be better executed.
The story leaves enough thing's happening that you do look forward to the next installment.
Pity there's no MP yet, but I understand there'll be an arena mod coming out sometime.
