These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Acceptable Targets: North Korean soldiers serve as your primary human opponents in the first game.
The KPA Nanosuits and the alien drones dropped by the Matrix-esque alien flyers.
It actually gets worse in Warhead; a major complaint about the original game is that once the ice hits, the alien flyers turn the game into a standard shooter, because they have only rudimentary AI and behave stupidly compared to the human enemies. Later in Crysis Warhead, they use squad tactics just like the North Koreans.
In Crysis 2, this title goes to the Ceph Heavies, which soak up a tremendous amount of damage and deliver just as much.
Designated Hero: Prophet in all three games when you add Legion to the mix. He knew that Nomad's team was going to be killed by the Ceph and stood by and let it happen, and then takes control of the Nanosuit forcibly from Alcatraz at the end of 2.
Disappointing Last Level: The first two thirds of Crysis have players traversing a vast open-ended environment populated by intelligent, squad-based human enemies, filled with side missions and numerous possible means of reaching objectives, and variable battle tactics that give players numerous means for handling each encounter with either stealth or aggression. Everything changes when the player enters the alien mothership in the seventh of the game's ten missions. First, they must complete a zero-gravity level, which has mixed reception; it's objectively amazing, but frustratingly difficult to control and easy to get lost in. After that, the player character emerges back into the same open world he had been exploring before, only now many of the paths are closed off and all the human enemies are gone, replaced with flying, hard-to-hit aliens who are far less intelligent than human enemies but take many more bullets to kill and render stealth practically useless. From there, the game turns into a linear corridor shooter, corralling players down a single path with no significant deviations and a commanding officer barking orders at them at regular intervals, all leading up to two long final boss fights that essentially amount to shooting a giant target a ridiculous number of times without dying, with no way to determine how close the enemy is to death until they finally kick it. Even with all these changes the game is still pretty good, but given the drastic, unexpected and above all completely unnecessary shift in style, it's easy to see why fans tend not to think highly of the final levels.
Ear Worm: Close Encounter. It plays in nearly a third of Crysis 2's "tactical arenas", ensuring you'll never get those cellos and violins out of your head.
Game Breaker: Proper use of the Invisibility Cloak mode can allow you to waltz through even the Harder Than Hard difficulty setting. It has been toned down a little in the sequel by putting a slight delay in the recharge time and making the enemy A.I. a little smarter and more aware.
However, the "Stealth Enhance" powerup (which greatly decreases the rate of energy consumption while cloaked) that can eventually be bought in Crysis 2 absolutely desecrates the balance of the game, turning even Supersoldier mode into a cakewalk for the reasonably skilled player, outside of the middle third of the game, where Alcatraz helps the Marines fight the Ceph (Also, most of the boss fights against the Ceph Pinger happen in this part of the game). Thankfully, after Eye Of The Storm, it's back to breaking the game.
Crysis 3 takes the stealth ball and runs with it, by adding the bow which can be fired while cloaked. Upgrade your stealth module, your power module and pick the heavy draw option for the bow, and only the bigger creatures will worry you. Even on the highest difficulty setting.
Pressing the HOME key on the numpad causes each member of the final boss fight in Crysis 2 to die instantly for no apparent reason.
He's Just Hiding: Crysis 3 does a lot to suggest Nomad might still be alive; the collectible intel lists a whole bunch of Nanosuit soldiers as KIA during Lingshan (including Jester and Aztec, half of Eagle Team, and even Big Bads General Kyong and Colonel Lee), but Nomad's status is simply listed as "redacted". Only people who've read the interquel comic released between Crysis 1 and Crysis 2 will know that Nomad took a rocket launcher to the face courtesy of the CIA and is confirmed dead.
However, another collectible datapad suggests that Nomad might actually be alive, and a CELL operative referred to as "Commander Lockhart" (another guy who was also thought to be dead), is looking for him.
Also, Alcatraz in Crysis 3. Intel files indicate his personality matrix was "47% corrupted" but SECOND decided to hold onto them instead of deleting them. It helps that Legion, which is still canon-ish, made a point that most of his memories are still intact.
Hilarious in Hindsight: In Crysis 2, when Gould nags Barclay to attempt to rescue Hargreave, unaware that he's been dead for over a century:
Barclay For all we know, Hargreave could be dead by now!
Ho Yay: Poked towards Nomad and Psycho, lampshaded in Warhead.
It's Short, so It Sucks : 3 gets this a lot by some fans. While they will admit that the graphics are at their best, and that the gameplay is pretty satisfying, the game can still be beat in just over half the length of Crysis 2 (depending on player skill).
Magnificent Bastard / Well-Intentioned Extremist: The curmodgeony, mysanthropic Jacob Hargreave, who reaches levels of successful, long-term manipulative deception previously seen only in Kane from Command & Conquer. For all his faults, it's hard not to agree that in most cases, his cold ways are the only option. Even Prophet acknowledges this.
Memetic Mutation: So, your computer's good, but can it run Crysis? No, it can't.
"MAXIMUM [Noun]!" (Adjusting the settings for the nanosuit, you'll often choose - and hear - "Maximum strength" "Maximum speed" and so on. The publishers even got in this, naming the special edition boxset "Maximum Edition".)
Paranoia Fuel: In Crysis 2, the Ceph Guardians that appear periodically. They are actively stalking you, specifically, because the Ceph want their tech back. And you never know if one is just hanging on the side of a building, watching you under its cloak... Until you unlock cloak tracing, at which point you can punch them, disabling their cloaking.
Poor Man's Substitute: Whenever a sniper rifle isn't available, you could put a sniper scope, laser pointer and silencer on your SCAR and set it to fire in semi-auto, making it a decent substitute. However, since you barely get any ammo for it, you'll mostly end up doing this with the inferior FY-71. While you can't attach the sniper scope to a rifle in the sequel, the ACOG provides enough of a zoom to still get the job done, though one shot won't drop Ceph infantry.
Also applies to the SCAR's under-barrel Gauss Attachment, which makes for a high-powered sniping alternative when combined with the SCAR scope.
"Ascension" was also cut out entirely from the PSN and XBLA ports of the game, suggesting either that Crytek couldn't or didn't want to program gamepad controls for the VTOL or, more likely, that they didn't think too highly of it either.
Warhead's Escort Mission. Delta (highest) difficulty level removes the ability to drive and use the turret of the APC. Instead of the character you are escorting drive whilst you gun, he drives off in a light humvee whilst you drive in an APC you need to stop driving and switch to the gun turret to use.
Also from that game, Gould's reaction when he finds out Prophet is dead.
That One Boss: Ceph Pingers have two different attacks that instantly drain all of your suit energy. They have a weak spot on the back, but they will ALWAYS face you, even if you're Cloaked, unless distracted by one of your allies. If you try to hide and recharge, they have a nasty habit of spamming more EMP, perpetually draining your suit. And you have to kill four of them!
There's a "boss" fight at the end of the freeway segment where you're piloting an APC in Crysis 2. The exit of the freeway is partially blocked, forcing you to go through a narrow doorway, and on the other side are two CELL APCs. They have anti-tank rockets which can kill your APC in one hit and fire in salvos of four at a time. Fighting past them is a frustrating challenge, but you have the option of just dismounting, going into stealth, and going around them.
They Changed It, Now It Sucks: In addition to the "consolitis" outrages, the Crysis 2 Nanosuit has undergone some changes to "streamline" the Nanosuit's modes. Armor mode now reduces your maximum speed and drains your suit energy at a rather rapid rate (the same as walking normally in Cloak mode), and Speed mode and Strength mode have been combined into the suit's default Power mode.
They Wasted a Perfectly Good Plot: Crytek did not incorporate Peter Watts' novelization of Crysis 2 into the third game. That means all the plot threads left hanging in Legion, such as Jacob Hargreave possibly being much older than 127 years, are not addressed at all. Alcatraz is also dropped entirely, in turn dropping the "nerd being turned into an alien machine while fighting a war that scales up far beyond his comprehension" drama in favor of "Prophet the Scary Black Man". To be fair to them, the novel does acknowledge as directly as it can without breaking the fourth wall that it and the games are not exactly 100% compatible, and some events in the book are "inaccurate".
What an Idiot: DARPA in Crysis 2 somehow concludes that the Marines that they're in the middle of deploying won't be enough and decides to bomb the dam and flood the city in an attempt to slow the aliens down. The aliens are nicknamed "Ceph", as in cephalopods. They're amphibious. Humans are not. Lampshaded by every single character.