A few good ideas, but Prospekt is hurt by uninspired design and infuriating combat encounters.
Having said that, it's a beat that for the most part I found myself happily nodding along to, and you know what? Prospekt did scratch my Half-Life itch a little. Not a huge amount - it's too fleeting and lacks some of the subtleties in Valve's design. For just over a fiver, though, it's a worthy scrap of canon.