More of what you've come to expect, which is mostly a good thing. Mostly.
Episode Two seems to be the exact same thing as Half-Life 2 was, but with advancements in the plot. I'm still deciding whether that is entirely a good thing. On the one hand, the formula for the Half-Life series has always produced favorable results. On the other hand, I'm getting kind of tired of being forced into situations where the gravity gun is my only option.
SPOILERS AHEAD!
The plot of Episode Two revolves around Gordon Freeman and Alyx attempting to make it to a resistance base up in the mountains so that they can stop an impending portal storm caused by the destruction of the Citadel. Fairly straightforward. However, as always, things don't go according to plan and the duo keeps getting sidetracked.
The gameplay is exactly what you would expect from Half-Life 2. This is its greatest strength and also its weakness. The game starts you off slow, giving you only the gravity gun to work with, and fighting off some lowly zombies. Soon, more weapons can be found, and the player advances to fighting antlions (including a new type), and eventually combine forces. Of course there is a large vehicle portion along the way, as well as obstacles that need to be taken care of by the gravity gun every thirty seconds.
This is good, in that I feel like I never stopped playing Half-Life 2. It is bad, however, in that I'm tired of being placed in situations where the gravity gun is required, simply to continue showing off the capabilities of the Source engine's physics. Situations where the gravity gun COULD be used, now there's where the magic would be found.
Level variation seems to suffer from the same dichotomy. I was completely unsurprised when I had to travel through abandoned mine type areas, battling spider headcrabs. However, it was still fun for me, and at no point did I become frustrated. I immensely enjoyed a room where I had to help AI fighters repel antlion swarms that were bum-rushing us through the various tunnels leading to the room we were defending. The woodland areas were a nice change of pace, although they still felt somewhat rigid and lifeless.
There are a couple of new enemies that I could see. The most obvious is the combine hunter. They are fast and heavily armed, but no match for a rocket, the secondary fire on the pulse rifle, or even a batch of shotgun shells in a pinch.
There were no new weapons to be found, which was kind of a disappointment to me. But, I wouldn't want Valve to start cluttering up the game with guns that all behave the same, and just look a little different.
The plot advancements were meaningful and in many ways, necessary. I won't spoil them, but some serious stuff happens. The plot may be what I enjoyed most about Episode Two.
Overall, if you're looking for something brand new to sink your teeth into, look somewhere else. However, if your Half-Life itch has started to flare up, this is the perfect way to satiate that need with a few hours of gameplay. I'm once more, interested in Half-Life. I'm probably going to lose interest and find many more games to play before Episode Three is ever released. Perhaps that is the whole point. When Episode Three does come out, I'll be itching to start swinging that crowbar once more.