In addition to standard W, A, S, D movement and shooting by pressing LMB (left mouse button), you can do a few other cool things. Hold the space bar to run. You can't shoot while you at it and your armor is reduced, but you will move much faster. Try the hit and run tactic, when you stop only for a second to shot and then continue running right after. Hold the shift button to duck (aka crouch). You can't move when you do so, but your range and accuracy are improved. Try holding RMB (right mouse button) right before you shot, it'll increase your accuracy. You still can move while aiming, although not as fast as before. Lastly, you can occasionally perform manual reload by pressing "R". It's faster than the standard auto-reload.
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