This is the only strip in the arc that directly references specific Metal Gear Solid events you wouldn't catch:

The evident one: Recolver Ocelot's hand is cut off in MGS. He replaces it with Liquid Snake's (Liquid didn't need it anymore). Through the arm, Liquid is shown to possess Ocelot with increasing persistence from Metal Gear Solid 2 onward.

The sneaky one: In Metal Gear Solid, Snake sneaks his cigarettes past a strip search before the mission by swallowing them (they are a usable item in the game--while they chop off bits of his health at a moderate rate, they make infrared sensors visible. So Snake sneaks his outsider candy into the theater with the same method. Why? Because the candy at big theaters like this is expensive! Sneak snacks! Snake sneaks snacks!!