On my fourth or fifth replay of MGS 3 and I've really come to appreciate The End, probably one of my favorite bosses in the series and one of my favorite bosses of all time. In a lot of games I like to keep a save right before a moment I really like, in MGS 3 I have saves for: The End's fight, the ladder right after The End (lol), and The Boss' fight.
It really feels like a Hunter vs Hunter duel in a dense jungle, this fight can take a WHILE for new players, so long that Kojima made The End just straight up die of old age if you save mid-fight and come back after a week or so. You can even pick him off earlier than usual by sniping him after a certain cutscene with a hidden SVD you can find early on in the game. But The End is too much fun to fight for me to skip unless I was trying to beat the game as fast as possible for a rank or something.
In my most recent replay of the game I forgot to pick up the thermal goggles (probably the most useful tool for fighting The End) in Sokolov's room like a total doofus. So I just rawdogged the fight by keeping low and looking out for the glare of his sniper lens, which looks deceptively similar to the glare of the sun if you aren't perceptive enough. After nearly an hour of stalking this old man and holding him up three times to get his camo, I took him out in my favorite way, a stamina kill by blowing cigarette smoke on that geezer (using the cig spray is my favorite way to take out all the bosses really, it helps that I always go for stamina kills to get their camo after their fights).
I'm not even joking the only similar experience to The End's boss fight in gaming I've had was playing old hunting games, or more specifically Deer Hunter II. Those games aren't afraid to keep you around for a while before you even find anything, which makes it even more exciting when you do; They tend to have really calming ambiance as well, I enjoyed that game a lot more than I thought I would.
All in all, I really appreciate The End and think a lot of games could use a similar approach designing their bosses.
(and a long ass ladder as a reward for beating them)