There are eleven single player levels in Crysis, seven in Crysis Warhead, eighteen in Crysis 2, and eight in Crysis 3 . Although these levels seem linear and straight forward, appearances can be deceptive. The Sandbox nature of the engine means there are multiple paths that cover all the options of pure firepower, vehicle usage and covert tactics. Some of the levels appear to have a time limit (the player's commander will hurry the player along) but actually this is not true and far more time can be taken over missions than it seems. (the only time there is an actual time limit is during Paradise Lost)
The player can use the audio boosting function of the binoculars or tactical visor and silenced weapons to follow a tactical/covert path using the cloak. Careful reconnaissance using the accurate map and the binoculars or visor allows marking of enemies on the map and on the HUD. The Map also assists in the setting of ambushes using objects, explosives, and carefully placed vehicles for distractions and misdirection. This approach can be used to deceive the enemy who will aggressively track their last known contact unless they perceive what they believe to be a new, more accurate, contact. Overall the Single Player experience is carefully weighted between suit modes, weapons and the AI as opposed to the player making progress using a purely brute force approach.