Found in: Prince of Persia: The Sands of Time (GameCube)
Unlocked by connecting the GBA version of Sands of Time to the GameCube version via the GBA Link Cable, you could play a full port of Jordan Mechner's original 1989 game on GameCube if you wanted.
Not the cheapest way to play, mind, seeing as you needed a Game Boy Advance, both versions of the game and the Link Cable. But do-able.
Found in: DOOM Eternal (Switch)
That's a lot of DOOM to digest — not an eternity's worth, but a hell of a lot.
Found in: Star Fox: Assault (GameCube)
Hardly the crown jewel in the Star Fox canon, but the Namco-developed Star Fox: Assault did have a trick or two up its sleeve — namely an unlockable version of classic shmup Xevious. The Japanese version also included Famicom titles space shooter Star Luster and regular-ol'-Earth shooter Battle City.
When you throw in bonus gems like that, even a lesser series entry starts to look foxy.
Found in: Celeste (Switch)
The full console release of Celeste contains the original Pico-8 version of the game, too. The smaller-scale original version was created in just four days when developers Maddy Thorson and Noel Berry took part in a game jam and it's accessible in the console version from the main menu once you find the computer room for the first time in Chapter 3.
Found in: Contra 4 (Nintendo DS)
Another heavy hitter in terms of unlockable extra games, Contra 4 on DS featured not only the original NES Contra, but also the sequel Super C — unlockable through beating four and eight challenges respectively in the appropriately named Challenge Mode.
In this case, the headliner was also a fantastic game, and only squeezing the third entry onto the DS cart could have improved this damn fine run 'n' gun package.
Found in: Sonic Adventure DX: Director's Cut
Various of Sonic's 8-bit Game Gear games were unlockable in the GameCube port of Sonic Adventure.
While you'd be pushing your luck to call most of them the 'best video games in other video games', the original 8-bit Sonic the Hedgehog and Sonic the Hedgehog 2 for the Master System / Game Gear hold a special place in our affections. The music alone from those two entries makes this worthy of inclusion. Tunes.
Found in: Pokémon Gold and Silver (sorta) (Game Boy)
The programming acumen of future Nintendo president Satoru Iwata famously meant that Pokémon Gold and Silver included not only the new Johto region, but also the entire Kanto region from Pokémon Red and Blue, too.
Doubling the size of the game and adding Pokémon and locations familiar to anyone who played the original game, it really felt like you were getting two games for the price of one. No wonder some people swear that the series peaked in Gen II.
Found in: Nintendo Switch (firmware version 1.0.0)
Okay, as a game hidden in firmware we've got ourselves another rule-bender, but we're on the topic of the great Satoru Iwata and anyone who had a launch Switch theoretically had access — at one time before connecting to the internet and updating the console's firmware, at least — to a special version of NES Golf.
Supposedly included by Nintendo as a 'charm' for the new console and a tribute to the Nintendo president who massed away in 2015, this hidden game was only accessibly if you set the console's date to 11th July (the day of Iwata's passing) and performed a 'Direct to you'-style gesture with the Joy-Con, a voice sample of Iwata-san plays and Golf (a game he programmed for Nintendo while working at HAL Laboratory) appears.
Easily accessible? Nope, but it's there. Or it was.
Here are a handful of excellent mini-game examples and random oddities that we couldn't leave without dropping a mench:
- The Touryst has some great games in its arcade, including a brilliant 'demake' of FAST - Racing League
- Not a game as such, but the imagined 8-bit handheld version of Banjo-Kazooie that the titular pair are enjoying on the save select screen is amazing for the chiptune rendition of the game's main theme alone, but watching Banjo and the breegull chilling out fireside in an armchair with a big chunky DMG-001 warms our cockles
- Xenoblade Chronicles 2's Tiger Tiger, the arcade mini-game you find in Tora's House is pretty great
- The 'play-while-you-wait' platform hopping Squid Jump game (above) in Splatoon. A shame that didn't make the leap to the sequel
- Demontower is an addictive, top-down, hack-and-slash roguelike found in Night in the Woods that'll keep you occupied longer than the main game if you let it
- All the versions of Mario Bros. to be found on the GBA's 2D Super Mario ports. Anybody who owned a GBA likely has access to one of those — very probably several. In fact, there may be more GBA carts in existence with Mario Bros. on them than not...
Thanks to Nintendo Life reader Franc001 for this list suggestion! Think we've missed an essential game-within-another-game? Let us know below and we might just add it to the list (or give it an honourable mention, at least).