Nice expansion but something is smelling stale.
WARNING:The following contains excessive ranting from a Half-life fan boy.
I was never a big fan of half-life. While it was hailed as revolutionary, to me it was evolutionary. All it basically did was add a story very influenced with that of Doom + some depth, NPCs and some puzzle solving. This is definably evolutionary but to me a revolutionary game would be System Shock
Fast forward to Half Life 2 and I started to love this game for few reasons but gameplay was not one of them. While HL2 was deemed as revolutionary all it did was improved upon things done in older games like Deus Ex, System Shock and HL1 and had a little more focus on physics. The Urban Futuristic and Post Apocalyptic theme appealed to me and so did the design for the combine race (right till the sound effects) not to forget the silent protagonist & no cut scene approach. This is the same reason i love Doom (hell + demons=relevant to my interest). To make it simple while these games lacked an outstanding gameplay their theme and artwork appealed to me and that's why they are 2 of my favorites.
Half-Life 2: Episode Two retains the same gameplay as Half-life2 with minor changes. Puzzles are still based on the games physics. The game maintains the linear gameplay which I loved but also tries a non linear approach in the car levels, where you have an option to find caches. This game also focuses on the new open area capabilities of the source engine which can be witnessed in the final chapters of the game. Apart from the facial expressions, nothing is really breakthrough about the games engine but whats really great is that this game looks good and runs smooth with everything maxed out, including resolution and Anti Aliasing. Physics are by Havoc so it wouldn't really count but they are implemented the best in this game.
The A.I is still strong too. The Zombies and Headcrabs run to their death, the Antlions do the same although they do fall back and the Combine soldiers play defensive unless they have a shotgun.
The best addition and probably the best looking thing in this game is the Hunter. They have a fantastic A.I, animation and render. I even tried to run them over with a car and failed miserably as they dodge it and it's hard to judge which direction they are going to jump. These guys are the freshest thing about this game despite their unbalanced strength.
The characters are great, some humorous lines here and there. Voice acting is one of my favorites. Gordon and Alyx's relationship is still the focus, they are probably going to do it in Episode 3 (Destroy the ship pervs). Also a little more about G-Man is revealed here, in fact the G-Mans seems to have a little emotion in his dialogs. Storyline depends on whether you like Half-life's story in general or have played the previous games. Ending is probably my favorite part, it lacks the over emotional feeling that you would expect from a Hollywoodish game and I didn't predict it either.
Besides the excellent voice acting, the game delivers the same quality in it's sound as usual. The moans of combines gives me the chill. The music is perfect for a futuristic action game.
Sad part about this is that it's getting stale. HL2 had quite a diversity in locations such as City 17, Ravenholm & Nova Prospek, each of those locations had a unique setting and memorable feel. However these episodic games have nothing special. In Episode two places like the hills and White Forest are beautiful and well designed but the Antlion cave levels were boring. What all these have in common is the lack of character what HL2 had in it's setting.
Excluding the Combine forces the rest of the enemies are still the snooze fest they were especially Ant Lions. The Zombies only get difficult when there are hundreds of them surrounding you and only appear as scary when they are running towards you with a grenade in their hand.
I really love linear games. In fact with all those sandbox a.k.a free roaming games coming out, the linear style will redeem it's novelty. Half-life is a perfect example of a good linear game, you have things that keep it interesting such as the Guardian Ant Lion Chase scene, The Strider Invasion, The Hunter debut fight and many more but what keeps all these things connected is what is getting stale such as constantly switch to Gravity gun and Crowbar to break crates, the overuse of ant lions and zombies which were boring in the first game.
The Bottom Line
Episode 2 is surely better than Episode 1 due to it's relevance to the main story & better production. It appears as a continuation instead of a filler. If your a Half-life fan you probably have got this already. If your new to the Half-life games play HL1 or HL2 to decide. I wasn't disappointed with this expansion but then again i had really low expectations for this one, but none the less i quite enjoyed it. Although the game features some boring enemies(Xen Race, Antlions) the combine race makes up for it.
What the series really needs is a long sleep before Half-Life 3. Episode 3 is supposed to be the last in the HL2 universe, if they decide to puke out more then I'm not tuning in to any future episodes.