In Tekken 5 you can play Tekken 1, 2, 3, and StarBlade.

Oh wow, having only played Tekken 6 I kind of want to get that now!

Pac-Man World, Pac-Man 2: The New Adventures and Pac 'N Roll all have ports/emulations of the original Pac-Man unlockable/playable within them; The New Adventures and Pac-Man World 2 both have an arcade, each of them containing multiple Pac-Man games (including the original)

Sonic Adventure DX lets you unlock various Game Gear Sonic games
Metroid: Zero Mission has the NES version of Metroid unlockable and playable
Super Mario Advance 1~4 and Mario & Luigi: Superstar Saga share one same remake of Mario Bros. that can be selected from the title screen.

@Hot_Anarcocoa I totally recommend checking this game out, I've been playing it a lot recently and it's truly fantastic.

mgs3 subsistence has metal gear 1 & 2 on it

@mellorine Thanks, I added all of those! Do you know which games are in The New Adventures other than the original Pac-Man?

@badwill Nice! Added!

i think the snes version has ms. pac-man, the genesis version has a """new game""" called pac-jr (not to be confused with the arcade jr. pac-man) that's ms. pac-man in all but name and a bit of changed graphics

the splatterhouse reboot has the og splatterhouse 1, 2 and 3 in it

castlevania dracula x chronicles has rondo of blood and sotn in it

Thanks everyone! Added all of those!

oh oh oh! warioware, inc. on gba has a version of the nes dr. mario on it! it's a tiny bit cut down (one music track vs two, slightly smaller game field) but it's a new implementation of the same concept with very few differences otherwise

@mellorine Hmmmm...I'll accept it! Tangentially, I always thought it was funny that the first time I ever played the original Star Fox was because they put the first level of it into WarioWare: Smooth Moves with motion controls as a boss fight.

donkey kong 64 includes the japanese arcade version of donkey kong as a minigame
left 4 dead 2 contains the full campaign from left 4 dead 1 and is playable using the left 4 dead 1 party, though it still uses the updated mechanics from 2 i.e. shoving

@Lynxelot Added!

oh yeah, jetpac for zx spectrum is part of dk64 as well, i don't know why i forgot that

pitfall: the mayan adventure also contains the og pitfall as a secret unlockable with a cheat code

contra 4 features both nes contra and super c as unlockables

@lynxelot updated and added!

GTA SA has quite a few arcade games you can play in it. they are parodies of already existing arcade games

@Pookiemookie I file those under original games made from scratch. Dr. Wario in WarioWare, Inc. is probably the most edge case I'll let something get for this list, I let it slide because it's so similar and also the same company.

Rampage Total Destruction has Rampage 1 and Rampage World Tour on disc.

@DustyVita added!
Thanks for all the likes everyone, this is my most liked list now!

The original version of Medievil is an unlockable in the 2019 remake

TimeSplitters 2 in Homefront: The Revolution

@Clearin Added!
@Androu1 Ah good catch! I was trying to think of a recent news story I had heard about for this list and this was it!

Pitfall: The Lost Expedition also has playable versions of OG Pitfall

Ridge Racer has a version of Galaxian in its loading screens

@JaxMagnetic I'll add Pitfall but I don't think I want loading screen games on here. Since they end once the loading is complete, you can't truly play the full game.

in the saturn version of die hard arcade you can get extra credits by playing deep scan, accessible from the main menu!

@ana added! Man, y'all have some obscure knowledge!

Oh wow, I should have known!
Ms. Pac-Man Maze Madness has the arcade Ms. Pac-Man on it, just like how Pac-Man World has Pac-Man
Pac-Man Party also includes Pac-Man, Galaga and Dig Dug

aaaaand I think that should exhaust the list of Pac-Man games with games in them, unless you're willing to count cases like Pac-Man: Special Color Edition for the GBC, which comes included with a version of Pac-Attack, similarly to Super Mario Advance. If that counts, Ms. Pac-Man: Special Color Edition comes with Super Pac-Man!