Basics
Basics
The Hazardous Environment Suit
The trusty HEV Suit has a number of functions that are useful for battling your foes. Health and Energy are displayed on the bottom left corner of the screen. Both of these variables can be restored by picking up the many health packs and power cells scattered throughout the game. When a suit function is used, a meter will also come up showing how much auxiliary power is left. This meter will recharge when the function ceases. The amount of ammo in the equipped weapon appears in the bottom right hand corner of the screen.
Press "F" to use the flashlight to make your way through some of the darker areas of the game. This function uses auxiliary power, but will recharge quickly. There is also an oxygen meter that appears when swimming. Do not let this meter drop below zero or your health will begin to deplete. When approaching harmful radioactive water, the suit will give off a distinctive Geiger counter sound.
Press the shift button to use the sprint function. This brings up a meter similar to the oxygen count. Mastering the "sprint jump" is necessary to cross some of the larger gaps in the game, and allows you to reach some interesting areas.
Use the Environment
Most items can be picked up using the "E" key, and many more items can be moved with the gravity gun. Try building barricades to ward off enemies and use larger items like barrels as platforms to reach new areas.
Throwing items can be an effective alternative to using a gun. Heavy items like radiators will crush most enemies in the game with a single hit. Large items can also be used as a shield by holding them in front of you.
Red barrels will light on fire after two shots, and explode with three. They will also explode on contact when shot with the gravity gun. Don't get too close to the explosion as it causes significant damage. When red barrels are grouped together, they can also set off a chain reaction of explosions that can demolish entire areas.
Supply crates have been scattered about the land by members of the resistance force. Look for the orange lambda symbol to locate supply dumps. Supply crates are small wooden boxes that have a small yellow sticker on them. There are also large green crates that contain an infinite supply of the ammo depicted in the picture on the front of the box.
Puzzles
Many of the puzzles in the game employ Half-Life 2's realistic physics. Keep this in mind when trying to raise a bridge or cross a gap. Remember: if it works in real life, it will probably work in Half-Life.
Most wooden objects can be smashed using the crowbar, explosions, or fire. Once the gravity gun is obtained, the same objects can be crushed by being thrown into walls. Keep an eye out for levers, valves, and power outlets. Many of the Combine's gadgets require a power source. If you can remove the source, you can remove the threat. Note: The advice in this guide is based on Half-Life 2's default controls.