I absolutely loved - and still do love - playing the original Crysis and its successors. With isolated exceptions (!) the game engine is superb, the AI excellent, the level design outstanding, and the production values top-notch. Crysis 2 and 3 made some concessions as console games - primarily in less-fluid combat - but still provide jaw-dropping graphics, meticulous design, good scripts, perfect voice acting, great music, and terrific gameplay. The boss battles in 3, especially, are just magnificent.
VERY IMPORTANTLY: Crysis 1 / Warhead also had "quicksave" so you could try and retry endless variations on tactics over the wide range of levels and combat situations, and take on even the toughest situations without frustration. This extended the replay value to nearly infinite and was, incredibly, dropped in the Crysis 2 & 3 as some kind of bow to console praxis. What a loss!
In Crysis 1 I disliked only the post-mine sequence, travelling through the cave; and I found the ice levels less intuitive and more linear than the first half. But, so much else was and is just wonderful.
Crysis was so hyped before release that massive numbers of gamers were poised to hate it. They found an excuse in the graphics settings, where Crytek had unwisely attempted some future-proofing. Despite it obviously being beyond the capabilities of 2007-08 GPUs, users insisted on turning the graphics "up to 11" - and then bitching about performance! One gaming website called it the worst game of 2007. Go figure.
In fact the game was incredibly scalable. I first played it on a GeForce 4 card with 256MB, on a circa 2000 Pentium. This was at minimum resolution, but it ran and was a blast. Today it runs on my Dell tablet. To ever question its playability was either specious trolling or truly ignorant. Sadly, all the fake-news bad press really hurt Crytek.
I constantly look for another FPS with anything like the gameplay and polish of the Crysis quad. But we get endless stupid melee concoctions. Instead of enemies intelligently taking cover, standing off, or flanking, they just mindlessly run at you. That's because melee requires only a fraction of the programming smarts as do Crysis-level ranged tactics. So - none of the elegant and addictive cat & mouse of Crysis.
When we do get something with a few brains, the combat mechanics (movement, weapon aiming etc) are wretchedly clunky compared to all the Crysis games. And of course without an OPTIONAL quicksave you have to repeat huge sections to make any progress; can't experiment; can't save interesting start points etc. You get sick of the levels and there is almost zero replay value.
We can only hope for another game series even approaching this quality. Sniper Elite (which does have a quicksave option) might, if only they will ditch the clumsy 3rd-person figurines and go all-FPS.