I'm not some trolling idiot, I actually love HL1... so please, at least read what I have to say before downvoting, don't act like that just instantly means I hate HL1.
Yes, Half Life 1 is one of the best games you'll ever play. Assuming, of course, that it was designed for its engine. Meet Half-Life Source, a game that was made on GoldSrc then converted to show off the new engine they had made.
HL simply wasn't designed for Source, and no effort was put into properly re-writing the game for the new engine. The AI is bugged to eternally walk into any wall, I've yet to see a working hitbox, and HL1's graphics are better than this remake. It's actually unplayable due to the scripted events being broken. Sorry, that door isn't opening.
So you may ask about the low playtime. Well, when I realized I wouldn't be entering the test chamber, I tried skipping forward a few levels with the map command. Guess what? BUGS! LOTS OF EM! Nearly anything involving AI interaction would NEVER happen, half the time your enemies can't even hurt you (and vice versa), and a few levelskips forward, I even fell out of the world once when I got hit by a box.
Overall, I'm scoring HL Source with a 3/10. A complete waste of money you're seeing here, it's got to be some sort of joke on Valve's part.
If you want to play the REAL Half-Life bug-free on the GoldSrc engine, click here.http://store.steampowered.com/app/70/