Your favourite secrets in games *spoilers*

What are the secrets you've uncovered, in any game, that you liked the most?

For no one to be unwillingly spoiled, I think it would be best to write the name of the game and in the next line, inside a spoiler tag, write about the secret.

Let's share secrets then!

Duke Nukem 64

Super Castlevania IV

There's nothing spoilery about it, so I'll just say it without spoiler quotes, but I'd say just about every time I stumbled on a new rare weapon in Fallout 3 or New Vegas.

The secret world in Super Mario World. That game is amazing.

I'm not sure if this is a spoiler or not because I've never been able to replicate it. I thought it was pretty hilarious though -

Daggerfall

So there are a few models in Daggerfall where you can see a pixelated boob. That was pretty common. However, one time I walked into a house and there were a ton of very scantily clad models in every room. It was clear that there was something naughty going on here. I saved it because wow. The next time I loaded that save, they were gone! One of the more unexpected things I've seen in a video game.

I would say that the warp pipes in Super Mario Bros 2. I know it's old, but I remember finding them and being able to warp all the way to the final levels and it was just amazing to me as a 7-8 year old. That and I felt like I had discovered them, more so than the warp pipes in the first game.

The Secret Cow Level in Diablo II was also so satisfying.

Also, the two secret levels in Doom II, Wolfenstein and Grosse, were very cool. I hadn't seen them until I played the XBLA version of Doom II, and they were a ton of fun. Secret levels in mid-90s shooters were the bees knees.

The secret ending to Far Cry 4

Super mario world

The Mega Man X Hadouken.

Getting the Z-saber and the gold armor in Mega Man X 3.

The Legend of Zelda: Link's Awakening

The way the shop worked, you would grab an item, take it to the shop owner and pay for it. If he caught you trying to leave he'd say "Hey are you going to pay for that?" and you'd have to go back and pay the man. However, you could take a route in the store that made his back turned from the door and you could straight up steal an item. This came in handy with the bow because it was so expensive. However, if you returned to the store, he would call you out for it, scary music would start playing and he'd kill you. Your save file would get renamed to "THIEF" and all the NPCs in the game would refer to you as THIEF for the rest of your playthrough.

Love all the dumb little Easter Eggs in Half-Life 2 and the Episodes, especially stuff like the Oracle Vortigaunt, the caches, Lamarr in the rocket and the secret G-Man apperances. One of the few games i'll replay just to look for tiny incidental things like that.