https://www.overclock3d.net/news/software/co-op_crysis_mod_targets_december_release_-_contains_crysis_and_warhead_campaigns/1
 
For those that want to re-experience the original Crysis experience in a new way, you should have a look at Crysis Co-op, a mod which aims to grant PC gamers the ability to play through the entirety of the campaigns of both Crysis and Crysis Warhead with your friends. All you will need is access to Crysis Warhead on Steam. In December, the modders behind Crysis Co-op plan to release the Crysis campaign section of the mod, which will utilise Steam to make Crysis' multiplayer modes usable. This will make the mod usable without a VPN or direct IP addresses. 

Using Crysis Wars' existing multiplayer mechanics, Co-op players will be able to revise each other using defibrillators, though this function is removed in the mod's hardcore modes. Co-op players can also decide which character they are playing as in Crysis Co-op.
 
Can you play Crysis Co-op?

As much as I loved Crysis then, I tried to play it about a yr ago and couldn't get into it. Besides never been much of a multi-player person either.