"Endgame" is a reference to chess. The Endgame in chess is the final few moves when both sides have very few pieces left (in this case, only Soap and Price are left to oppose Shepherd).
The player will start this mission with whatever weapons they finished the previous mission with. However, if the player ended the previous level with AkimboTMPs, they will start this mission with only one.
When the player looks at a friend on the PlayStation 3 or Xbox 360 who is playing the very end of this mission, it does not say Endgame. Instead, it says "The Ending" which may mean that the mission was originally supposed to be called "The Ending". This only occurs on the second part of the mission, as "Endgame" is used before falling over the waterfall, and then "The Ending" is used afterwards.
The multiplayer map Rust is based on the end of this mission.
If the player kept a SCAR-HThermal Sight from the previous mission and use the scope onto Shepherd's boat, there are three hostiles. Somehow, Shepherd is not there. Even if the player launches a direct hit on the soldiers on the Zodiac or hit it with an AT4/RPG-7, it will not be destroyed.
According to the "_introscreen.gsc" the mission was at one point called "You Can't Win A War With A Bullet".
According to the "af_chase" fast file, there was one more objective: Shoot down (possibly a helicopter) (precachestring( &"AF_CHASE_FAILED_TO_SHOOT_DOWN" );)
If the player dies while driving the boat, their body will levitate above the water, and Price will also die for no apparent reason.
It is possible to get onto one of the bridges with the boat. If so, the player will notice that the boat drives along land the same way that it drives on water.
At the part where the river widens and the first Little Bird appears, if the player goes near the left bank he can see two Opel Blitzs with the iron cross.
The OpFor on the bridge where Captain Price warns the player about RPGs will just stand there after firing their RPGs.
Though the player is fighting OpFor and Shadow Company at the same time, when chasing Shepherd through the first few caves, the OpFor tend to focus more on the player than on Shepherd, however, this is most likely for balancing reasons.
At the part when Price shoots down the Pave Low, Price's name will appear as Cpt. Price, not Captain Price. This also happens before the player gets into the boat.
Shepherd's boat is forced to slow down considerably to board the Pave Low, giving the player time to catch up. If the player can reach the Pave Low before it lifts off, the player will pass right through it, revealing that it is not actually a solid object.
If the player stays close to the downed helicopter, he can actually get close enough to knife Shepherd as he is running away, but the knife goes through him and doesn't affect him, as Shepherd isn't scripted to die at the moment.
Before Shepherd runs, he is in a prone state, and then when you get near him he quickly gets back up and starts running.
The truck that Shepherd leans on can actually be seen outside of Rust.
If the player doesn't get close enough for Shepherd to attack him, he opens a conversation with the player. He says: "You know what they say about revenge... you better be ready to dig two graves... Go ahead and end it. It won't change anything... Hmph... I knew you couldn't do it... You're a good warrior... but you could never take that extra step... to do what was absolutely necessary."
If the player stands behind the barrel Shepherd is standing next to, the player can swing his knife and slash the General from the other side of the barrel without engaging the battle sequence. The same sound can be heard as if he were slashing an enemy, and blood can be seen spraying from Shepherd.
The blood splatters on Soap's gloves when crawling toward the .44 Magnum are completely identical.
The player can actually pull the knife out of Soap's chest before being prompted to. While Price and Shepherd are fighting, after the player is able to see Shepherd's knife, (i.e. when Shepherd kicks Price down) they can repeatedly tap the "use" button to start pulling the knife.
There is an Infinity Ward logo on the blade of the knife.
When Nikolai's Little Bird comes in to evacuate Soap and Price, there isn't a pilot in it before it lands. When the helicopter does land, the door does not open at all; Nikolai just appears outside of the helicopter.
Nikolai is wearing a pilot uniform in this level. But in "Prologue" he wears a combat uniform after he lands his helicopter.