Call me late to the party, but just having gotten Orange Box a few months ago and having just played through the joy that is Portal, vanilla Half-Life 2, and Team Fortress 2, Half-Life 2 : Episode 1 is... Kind of a letdown. Let me explain.
Half-Life 2 is a romp. There is an incredible depth of experience, from frantic vehicle sequences to great physics set pieces, high-powered high-tech platforming, and yes, even though I don't enjoy it, silly infected human shooter elements. In all, a fun, funny, varied experience.
Half-Life 2 : Episode 1 is none of that. It is some kind of a lame survival horror game. I spent like four hours underground. The part where you're waiting for the elevator? Incredibly frustrating. Look, I don't want to fish around in the dark. If I wanted that, I'd play Doom3 or some other trash.
So now that I'm above ground, it's a little more interesting, but it's hard to stay with it. It's a little disappointing. Where are the swinging pillars smashing my eneies and zooming vehicles? It's like Alyx just does all my work for me. She gets a sniper rifle? Where's my damn sniper rifle? I'm like the bait just dragging dudes with head crabs all over the place for her to shoot.
I guess that's what I get for playing an expansion to a game two years late. The shine's off.
But don't let that dissuade you from the Orange Box. The three titles above are surely worth it, even if you never play the episodes.