I too have been looking forward to this game for some time - but I was mostly underwhelmed with this release. It's a shame, as I am all in favour of episodic games.
Perhaps it is my advancing age, but this was simply too much of the same old run and gun (with a boss or two, of course, at the end). Like, been there, done that, umpteen times! Fear, or even Doom (which didn't do much for me) did a better job with this uninspired approach, and this is no foundation for a long term franchise. There was little of the great story we were promised, and little to keep a thinking person interested. I could live with the length if some originality had been there. Though Jessica is cute (which may serve its purpose for the juvenile market), her role is a simple rip-off from HL2.
And the run and gun I found pretty straightforward at the moderately difficult level. The AI is average at best.
Graphics and sound were mostly good (to be expected with the source engine), with some spectacular scenes.
I don't regret the $20 and will not give up on this game solely based upon episode 1, but this team (or tribe, if they prefer) needs to bring something fresh to the genre if this series is to go anywhere far. There are HL2 mods out there with greater creativity.