GOG version of Crysis is DRM-free, you don't need Origin or any sorf of activation software.
Regarding mods - they should work on any version of the game (Retail/Steam/Origin/GOG).

the bit about children makes me read this topic. the OP stated EULA in general I did read a review about "signing over your kids" whle I have no kids myself this made me think thrice about purchase. I have one Niece! being we are in a state of pollitical upheaval right now and EA is an uppity bunch of frankenstiens! This didnlt really surprise me. But I read the entire agreement. nothing about signing anything over to a higher power. oh well. no more John Hurt in 1984 for me! That movie can get you wary about EA EULA agreements! LOL I am going to buy it anyway. I played a similar game to this back in the day, the same year or so this game was made(don't recall the name of it except it was a covert'soldier who modded his arsenal.) And oh well! I am a gambling man! GOG Strips EA's DRM powers. As blakstar stated, and quite a number of you posters agree with here!
Thank GOG for GOG!
GOG bless em!