I enjoyed this game.It exploded the potential of a modified version of an old engine like GoldSrc (the original Half Life). Most features from Source Engine (Half Life 2) are partially integrated into, giving me a "what-if Half Life 2 was made into the same engine as the first one, instead of creating a new engine?" feeling (not to mention some elements from the 'Portal' videogame). And all of it in less than 2GB? Awesome! Nothing else to say than I'm impressed. Good work!
By the way: I managed to make the game playable with gamepad. It's working very fine, even on vehicles. If you're interested, I'll share the configs to you.