MK3A2 Grenade

The Hand Grenade is a weapon used in Half-Life 2. Most Overwatch Soldiers carry at least a few of these and use them to flush out and/or kill enemies. This grenade is most likely fictional and looks more like a gas grenade, with its cylindrical shape, than a traditional fragmentation grenade, even though the designation "M83 Frag" is printed on the top. Unlike the Half-Life Grenade, this one comes equipped with an electronic-chirping timer and a red light which leaves a trail when thrown after the pin is pulled.

The hand grenade is first acquired in Half-Life 2's third chapter, Route Kanal.

Usage
When thrown, these hand grenades have a fairly low-bounce but due to their cylindrical shape, they will roll a significant distance if they land on a smooth surface, so take that attributes into account when throwing them. There are three ways in the game to throw a grenade: Pressing primary fire performs a standard overhand throw with a high arc and considerable momentum, this can be used fairly accurately for long range targets, but using this method, the grenade will usually bounce and/or roll a considerable distance once it lands. Pressing secondary fire performs a light underhand toss, this is more precise than the standard throw and can be very useful. If the toss is aimed towards the floor the grenade will simply drop to the ground, but if the toss is aimed up, the grenade flies in a small arc, which is excellent for getting grenades over obstructions like walls or fences. Finally, if the player crouches and press the secondary fire button, the grenade will be rolled along the ground. This is an excellent way of getting the grenade under obstructions, like a chain link fence, for example. Be careful to only do this on fairly smooth surfaces where it will be able to move far enough away quickly. There is a fourth way to use grenades that involves using two at once. Any grenade caught in the blast of another grenade with go flying in a direction opposite the blast without being blown up. This can be used to punt grenades long distances around corners by throwing one grenade and throwing another right next to it, a tactic that is more useful for showing off rather than during actual combat.

Gordon can pick up active grenades, either with his hands (by pressing the action button) or with the Gravity Gun and throw them away (or back at the enemy). Using the Gravity Gun as a grenade launcher has also become a popular tactic and involves dropping a grenade at Gordon's feet, quickly switching to the Gravity Gun, picking up the grenade and launching it. This technique is very commonly used by players of Half-Life 2: Deathmatch, who call such Gravity Gun-thrown grenades "grav-nades", with the only difference being that they will rather throw the grenade into the air than at their feet (which is possible due to the time needed to switch to another weapon being shorter in HL2:DM than in the regular Half-Life 2). Launching grenades from the Gravity Gun allows them to go farther and faster; but because there is more power in the throw, the trajectory is slightly different, so adjust the aim to account for that.

Tactics
Utilized properly, grenades are a very useful tactical tool. Besides simply killing enemies, they're ideal for flushing out entrenched enemies, forcing soldiers out of cover, scattering concentrated groups of enemies, knocking over turrets that are otherwise hard to access, and even destroying out-of-reach power sources for forcefields.

Grenades are also very effective against zombies, as they generally move slowly and make no attempt to avoid the blast.

If a soldier throws a grenade at Gordon, quickly equip the Gravity Gun, pick the grenade up and throw it back. Killing a soldier with his own grenade unlocks the Hot PotatOwned achievement. The grenades can also be shot away with firearms if there is no time to switch to the Gravity Gun. The Shotguns double-blast is the most effective.

Zombines sometimes use live grenades as clubs, unwittingly blowing themselves (and anyone close by) up in the process. It's possible to shoot the grenade out of their hand, but it's easier to use the Gravity Gun to pull it out of their hand and throw it away (or back at them). Grabbing a zombine's grenade with the gravity gun unlocks the Graverobber achievement.

Trivia

 * In a few scripted sequences in Episode Two, Combine soldiers throw the grenades back. As well, at one point, Gordon comes across a dumpster, with a fast zombie digging out boxes. If the player throws a grenade in, the zombie will throw it back out. If the player throws another grenade, it will blow, and the zombie will jump out in flames.

List of appearances

 * Half-Life 2 
 * Half-Life 2: Deathmatch
 * Half-Life 2: Lost Coast
 * Half-Life 2: Episode One
 * Half-Life 2: Episode Two