Things you can do in this game/facts:
When people say nobody knew about Raiden it’s true. The promotional trailers showed several scenes with Solid Snake in different locations. In the final game, Raiden is involved in the same scenes, but in Snake's place. Kojima used CGI to cover up Raiden and no one knew of his existence until the game was released. His VA was also not allowed to speak about him
Kojima produced notebooks for the whole team to write their ideas in and he would see each day which idea he liked the most and tested it out to see if it could be programmed in. The Coolant spray and the sneak peak move are some of these
The script is over 800 pages long
According to Kojima the opening scene where Solid Snake throws his lit cigarette into the Hudson River caused some negative responses from fans, so in the later games Big Boss or Solid Snake are always seen discarding their smokes properly and avoiding littering whenever possible
The game's plot was inspired by an article in the news Kojima read about the US Government shutting down the popular music sharing site Napster
The programmers, artists, and game designers had to undergo a series of lectures and real-world counter-terrorism mission simulations in order to perfect the AI routines for the enemy soldiers
Apparently Kojima rushed to have the game finished before the end of 2001 because 2001 is the Year of the Snake
Because of 9/11 the devs removed all American flags from the poles along Wall Street and atop Federal Hall. Originally after killing Solidus, Raiden was supposed to cut the flag down from atop Federal Hall to cover Solidus's dead body. The animation is still in place of Raiden raising his sword and then slicing it down, but the flag was removed
If you take a photo of one of the girl posters in the lockers or Olga’s breasts Otacon will say he’ll make a back up of it
If you take a photo of Scott Dolph once Otacon will ask if you’re a fan, if you take another one he says he’ll make a panel to hang over your bed since you like him so much, and the third time he’ll angrily tell you to stop sending photos of him
If you take a photo of The Vulcan Raven action figure Otacon says “It explains a lot” and “not that there’s anything wrong with keeping it to yourself”
A photo of a marine in his underwear will cause Otacon to laugh and if you keep sending him more he’ll gradually get angrier
If you sneak up behind the marine and start comboing one they’ll all start colliding like bowling pins
If you point the directional microphone at Emma’s parrot and keep saying “you must be Ames” the parrot eventually starts saying it with you
If you point the directional microphone at Emma during the sniping part she’ll comment on what she thinks of Raiden and say she “has her own ideas about that hair” and if you call her Raiden will angrily say his hair is real
If you look up at the seagulls in first person view for a few seconds you’ll get shit on
If you give Snake the shaver at the beginning of the game he’ll be shaven by the end of it
When you meet Snake for the first time call him and he’ll be asleep, if you call him again he’ll yell “LIQUIIID”
If you spray unconscious guards with the coolant they’ll snore rapidly
When logging into the first node and your birthday is the same as your PS2 or PC’s internal clock a happy birthday message will appear with a cake
If you enter the name “Hideo Kojima” “Yoji Shinkawa” or another staff member it’ll automatically put their birthday and nationality
If you lean against a poster of a Konami girl and tap the boobs it’ll make a bouncing sound and if you press the bottom of the bikini it’ll trigger alert mode
If you keep shooting seagulls the Colonel and Rose will get mad at you and the latter won’t save your game until you apologize
If you don’t get out of the way in the strut L cutscene the soldier will piss on you and if you call the Colonel he’ll say this is the reason they’re called wetworks missions
When a third playthrough is started on tanker or plant Snake or Raiden will be wearing sunglasses
Fatman is named after the atomic bomb that was detonated over Nagasaki

The first names of Otacon and Snake respectively are Hal and David, and the tanker is called the Discovery. Remind you of something?
If you trigger alert mode on arsenal gear when you’re naked and press against the torture device as the soldiers enter the area after they clear it one soldier will look at Raiden and say “wish I had that”
After Snake gives you the high frequency blade knock him out and you can get his dog tag, if you do this before the second fight in jejunum and change the difficulty level you can get the dog tags of Meryl Liquid or “Iroquois Pliskin”, if you do this on extreme difficulty you’ll get Kojima’s
In the ending cutscene when Snake and Raiden are talking(peak dialogue btw)Vamp can be seen in the background watching


Is this the most detailed game ever made?