Now that you are somewhat familiar with Half-Life and First Person Shooters in general, take a look at these medium-advanced tips for the game.
Fisrtly, an important aspect of sucessful playing is your train of thought. This isn't the most important thing in your life (I hope!) and is certainly not all that has to be on your mind while you play. If you really want to advance, you have to dedicate time to playing this game. If you expect to be great if you play in short 15 minute sessions once a week, it probably won't happen. So you have to be mentally prepared to play! (Don't I sould like that game trainer from the Blockbuster commercials?)
But the point I was trying to get at is that playing this game is just as much mental as it is skillful. There ARE puzzles. Always think outside the box. If you have a little trouble with one area, look around and study as much as you can. Then take a break. So that night you can think about how to get beyond that point. Now without further adue, here are some tips:
-Look for hidden passages or alternate ways to go. They are often rewarding and less dangerous.
-Strafe around corners, that way you will be able to see any threats faster
-Use the shotgun in confined spaces and the pistol or 9mm AR in open spaces
-There are also creative ways to kill enemies. If there is a beast that seems impossible to kill, look for that crank that drops a crate on it, or that loose electic wire to lure it into...
-Take a risk. Can you really make that jump? Save the game and then try it.
-Vents are often the road to travel in this game.
-New enemies will be discovered as you pregress through the game. Don't see a new one and scream "MOMMY". Try to kill it using whatever you've got.
-Weapons are always nicely placed in the order of when you need them. If you pick up a remote bomb, perhaps you will be facing a bunch of marines where leaving a bomb for them to trample over is best.
-Within the same note, weapons or ammo might hint to you of what to use to kill that new creature. If the room is lined with shotgun ammo, don't use the rocket launcher!
-If you hear an enemy nearby, crouch and then continue to move on. Chances are, the enemy won't react as quickly when you see it.
-Also if you hear an enemy, it sometimes may be coming from a wall that is about to be blown through. If you hear the Slave's grumbling, look around for a door that might be blown open.
Ah, you must be a real master now. Play around with these tips and then come back to the advanced player tips!