When the player has climbed to the top and is getting up from the cliff, Roach's shadow is visible. From this it is shown that he is wearing a boonie hat just like John "Soap" MacTavish is, however the shadow will disappear as soon as the player stands up.
When climbing up after the second jump, Roach's shadow consists of two floating arms which disappear before pulling out the ACR.
On the first jump, if the player hesitates to jump when Soap does, he will start climbing, stop and wave to Roach to jump. He will keep doing that until Roach attempts the jump.
If the player presses the melee button while holding the ice picks both ice picks will swing as if they were a melee weapon.
The player can hear Roach yelling if he falls off the mountain.
Should the player decide to not shoot either of the two-man guard patrols after climbing up, Soap will do it while chastising the player for not helping out, saying "I guess I have to do everything?" The second time, he is a bit more agitated and replies with "This would be a lot easier if you do some of the work."
Should the player instead kill both guards, Soap will give his standard lines as though the player had taken them down together as normal. On other occasions he will not say anything at all, and continue as if nothing happened.
If the player were to go ahead of Soap and shoot one of the enemies in the second pair, and damage but not kill the other, Soap will kill him and say "There is the reason we brought silencers."
Soap says he will help Roach with a Thermal Scope, sniping enemies. However, his M14 EBR has the default scope attached.
If the player picks up a weapon from the enemy, Soap will advise the player that un-suppressed firearms will attract a lot of attention.
If the player attempts to kill a guard with the USP .45, Soap will say, "That was sloppy."
If the player kills a guard first when Soap says "He's mine", he will reply after the player has killed him "Then again, maybe not" or "Never mind".
If the player reaches the fueling station fast enough, sometimes Soap's script will mix around out of order.
If the player does not kill or alert any enemies while sneaking through the base to the fueling station after separating with Soap, they will receive the Ghost achievement/trophy, and MacTavish will comment, "No kills, no alerts. Impressive, Roach."
If the player destroys a jeep when there are no enemies around (or are unaware of your location) MacTavish will comment "Wow, I wonder if they'll notice a flaming wreck in the middle of the road", although the subtitles say "Gee, I wonder if they'll notice a flaming wreck in the middle of the road."
If the player goes to the hanger with the intel before they meet up with MacTavish, there isn't anyone in the hanger. But when the player does meet up with him, there are two NPCs in orange uniforms repairing a MiG-29. Killing them will have no effect on the mission, and even if you miss they won't pay attention to you.
Strangely, Soap won't cover the player if their cover is blown, but instead will tell the player that: "You've alerted a guard, stay out of sight."
Soap's speech at the beginning can be stopped if the player shoots one guard first.
If the player takes out the USP .45 and looks at the hand holding the Tactical Knife, Roach's gloves appear to say "Snowfinity", a reference to Infinity Ward.
If the player moves up to the window where the ACS module is, an APC located outside will vanish as soon as the intel is collected.
If the player gets seen on the way to the hangar and leads guards to the area where Soap is hiding, he will comment, "Brought some friends with you?"
Once the player enters the hangar, the ice covering Roach's goggles and ACR seems to melt away.
This mission connects to the Rangers mission "Wolverines!", as Soap and Roach are tasked with getting the ACS module, the "device" in which the Russians use to cover their attacking approach to the U.S.
The ACS module is part of the US Attack Characterization System, which would normally give accurate early warning of impending assaults based on satellite intelligence.
If Roach shoots the guard before MacTavish assaults him, MacTavish will stop and take up a shooting stance, even if the guard is dead.
The guard in the hangar starts to bleed before Soap stabs him.
While driving the snowmobile down the large hill at the end, hitting Soap's snowmobile from behind will kill the player and send them flying.
If the player is killed when driving up a large hill, the camera will still go over the jump.
When at extraction, Kilo Six-One will say "We're at bingo fuel," but the subtitles say "We're getting close to bingo fuel."
This part was referenced in the Battlefield: Bad Company 2 mission "No One Gets Left Behind", in a conversation between Haggard and Sweetwater in a quad-bike race, with Sweetwater saying, "If this was a snowmobile race, I'd take you down!" to which Haggard responds, "It's not a snowmobile. snowmobiles are for sissies!"
In the Worldwide Reveal Trailer, it shows Soap being killed after being caught by the soldiers in hangar.
In the movie Abduction, it is seen Nathan playing this level or could be the Special Ops mission Race, and when he pauses it, it doesn't go to the pause menu.
The ACR has more zoom on the Red Dot Sight. This is easily noticed when the player compares it against an AK-47 Red Dot Sight.
In the E3 2009 demo, the player's objective is to download data from a computer, but in the final version of the game it is to retrieve the ACS module which are both on the same table. Also in the demo, Soap has a timid English accent rather than a loud Scottish one. This could mean that in conceptual stages Soap was English or Infinity Ward hired an uncredited English actor for the demo before hiring the true cast. Also, the background music while being stealthy is from Call of Duty 4.
Back during the E3 2009 demo, the tactical knife on the silenced USP .45 that Roach has as a sidearm looks like the Call of Duty 4: Modern Warfare melee knife instead of the normal Call of Duty: Modern Warfare 2 knife, and slashes the knife instead of stabbing with it.
In the early development of the level, Captain Price was scheduled to be with the player and the player would control Soap, rather than Roach.
In the 2009 E3 demo, intel 2 does not appear.
If give ammo cheat is used, the player could notice that the ACR is special not only for three attachments and unique camouflage, but also for 840 capacity instead of usual 630.
If Roach crouches near a heater, the frost around his goggles will melt. When the player leaves, frost will appear on the goggles again.