The icons around the active weapon are the combat options. These are:
Precision Strike - with this command, you can target any body part of the opponent. You can choose from the head, torso, arms and legs. Shooting at the head, carries a 60% penalty to hit, but it deals damage higher by 35% and can cause the enemy to be unable to tell the difference between the friend and the foe, or starts taking irrational actions. For example, he may start wasting AP on moving in the wrong direction. Firing at the torso, carries a penalty of 30% to hit and it deals 20% less damage, but it instead decreases the value of the armor of the target. Shooting the arms has a penalty of 35% to hit and damage lower by 30%, but it can damage or destroy the opponent's weapon and also decreases their chances of a successful hit. Restrictions are identical in the case of hooting the legs, which mat slow down the opponent (it decreases the opponent's combat speed, or provides a penalty to AP), or throws the opponent to the ground. Depending on the opponent, each body part can be damaged even several times, which makes it more and more difficult for the opponent to take part I the battle. However, there are opponents, in which you can damage only one, or two body parts. This is especially true in the case of large robots, such as Scorpitrons, and meson cannons. Humanoids with mechanical elements can be shot in all four strategic spots. The cost of a precision strike is identical with that of a regular one. Due to their handicaps, precision shots are difficult to pull off at the beginning of the game. Later though, thanks to better weapons and better skills, you should succeed to take one more often. You do not use them in the case of weaker opponents, who die anyways from one, or two hits, but they are invaluable in the case of battles with stronger ones. When you decide on a precision attack, try to be picky with targets. Shoot at arms of the opponents that use the strongest weapon, shoot at legs of the fastest one and at the torso of those with the highest CON. Remember that you can take a precision shot from any weapon, with the exception of heavy weapons, machine pistols and shotguns. Assault rifles in the burst mode can shoot precisely, which is worth using to your advantage. A burst of two bullets of a machine gun is more likely to cause the effect of a precision shot than one bullet. This mode of attack is especially useful in the case of melee weapons with cheap attacks. A character with 8 AP and attack cost of 2 AP has, as many as, chances of a successful attack. Still, try not to use precision strikes too often. Regular shots carry a lower risk failing, and they may prove as effective.
Crouch - increases the chances to hit by 10% and chances of evading by 20%. It costs 2 AP. Once you crouch, the character will be unable to move, unless you use that command again, to stand up (another 2 AP). At the initial stages of the game, it is especially useful because of the +10% to hit. At that point, the Rangers are not well-trained enough with weapons so, the 10% can make quite a difference. Once the party is well-trained, it is going to pay off more, if you carry AP over to the next turn. Of course, on condition that the character is not in a very bad situation (e.g. directly in front of an HMG), because the + 20% of protection may save your life. Apart from that the character crouches automatically and receive all the bonuses if, e.g. you stop next to a cover (e.g. a crate a fence) - you will be able to tell those spots by the white shield icon that appears after you roll the mouse over them. If you want to leave the cover, you first need to command the character to stand up.
Ambush - The character will end the round going into the Ambush mode. This means that they will shoot at the first target that steps into their range of attack (the red field). An useful option when we try to lure our enemies, especially when using a sniper rifle or assault rifle. It is always better to fight by waiting for the enemy to come near you than rushing at them. The cost of Ambush equals the cost of attack. Remember that choosing this option will end the round!
Swap Weapons - swaps weapon to the one in the other hand. Free to use. Some short-range weapons are not are better (automatic) or better (shotguns), so it is always better to be safe on both sides. Apart from that when somebody is standing right next to you, hitting them with a wrench can deal the same amount of damage - if not higher - and saves up ammo.
Switch Fire Mode - you can switch between fire modes (especially in the case of automatic weapons) - to fire one single bullet or a burst. Modes that use up more AP and ammo deal more damage, but this decreases accuracy and you use up ammo faster. If the opponent is weak and he is not too much of a threat, always use the less-consuming mode. Also, change the mode to single at the end of each turn, in the case of NPCs that you included in the party. This will prevent them from wasting too much ammo in a silly way, in the case in which they defy control. Changing the mode does not use up AP so, you can switch, check out the chances of hitting and switch back.
Reload - the cost to reload usually equals the cost to shoot + 1, or the cost to shoot itself. You always need to remember to enter combat with your magazine full. You also need to reload whenever the weapon jams.
To simply attack an enemy, you just have to click on him. The hero will shoot using the options that are currently selected (for example Crouch mode). There is also an alternative - the free aim mode. Click on the icon of your weapon and then select the place that you want to fire at (it works also outside battle, when you for example want to shoot at a friendly NPC). Free aim is particularly useful with weapons that deal AoE damage, like for example shotguns or grenade launchers, to make sure that you hit as many enemies as you can and do not hurt your allies.