Few sequels are good, Half-Life 2 Episode 2 is fantastic!
Just when you thought it's the usual level design formula, Ep2 will surprise you again, and this time with a higher adrenaline rush via the scavenged Mustang. Combat and overall gameplay is a bit harder than the previous episodes, given new deadlier enemies, but if you played through the first two before, it shouldn't be a problem.
I shall say, Episode 2 scores high on creativity and sincerity in the FPS genre, not just due to the Gravity Gun puzzles, but in the overall interaction process and the excitement of anticipation the game provides for the player. Lastly, they finally made great use of grenades here!
KingLim