You put a “2” behind a game title and you’ve got a safe bet: more of the same. Its makes it easier for developers to release another game, and players get what essentially amounts to more levels of a game they already like.

But there are some that dare to be different, and turn the entire idea of franchise gaming on the ear. For the purposes of this list, games that jump between generations are omitted as upgrades and changes are expected on new hardware.

Castlevania II: Simon’s Quest (NES)

The first in the series is a great linear dungeon crawler. Its proven the test of time, and started a series still going very strong today (in 2D no less!). But wow, Simon’s Quest was really different. Its much more of an open world, introduces RPG elements, and even adds a night & day passage of time. Modern Castlevania games balance elements of exploration and action well, but this was uncharted territory at the time. Castlevania III, while a fantastic refinement of the game play of the first, misses out on the stuff in Simon’s Quest.

TMNT 2: The Arcade Game (NES)

The super hard NES side scroller based on the exploits of the Teenage Mutant Ninja Turtles has its share of fans, but about the same time an arcade game came out that looked and played a lot closer to the animated series. A variation of the gameplay found in Double Dragon, the turtles took on hundreds of Foot clan ninjas as well as Baxter Stockman, Bebop and Rocksteady. The NES port of the game slapped a roman numeral two at the end, as well as adding a couple new levels and bosses. Its a far greater game for all the changes, and subsequent TMNT games, regardless of platform, have tried their best to duplicate this formula.

Halo 2 (XBox)

The original Halo kept the XBox alive as it struggled to compete against the Playstation 2 and Gamecube. When Halo 2 came out, it pushed the platform forward and gave it one of the most popular games ever made. The changes weren’t readily apparent, but as the community got the game, they became glaring. The primary weapon of the original was gone, replaced a machine gun and the battle rifle. The pistol had been nerfed to the point of uselessness. Players no longer had to put up with split-screen, getting the option to play online, giving the game a long shelf life. Even the single player campaign took you out of the helmet of the Master Chief for the first time, forcing you to play as the mysterious new Covenant character The Arbiter for half the game. In Halo 3, the pistol, the AR, and a full Chief-only campaign returned.

Zelda II: The Adventure of Link (NES)

Arguably the greatest masterpiece of the NES, The Legend Of Zelda deserved a follow-up. This game dropped “The Legend Of” along with all the gameplay of the original. Link was now a teenager, and travelled Hyrule’s overworld more like a mapscreen. When approached by an enemy or entering a dungeon the game changed to a sidescroller where link had to duck, jump and slash his sword more skillfully than before. Add on an experience point system and you’ve got a fundamentally different game, with some familiar music and characters. The next game, A Link To The Past, favored the originals gameplay while upgrading for the new Super NES.

Metroid II: Return of Samus (Gameboy)

Many will credit Super Metroid as a giant leap over the original in both gameplay and storytelling. But few ever mention Metroid II on the original GameBoy. This game continued the exploits of Samus Aran, as she travelled to SR388, to exterminate the Metroids. Along the way, the wave beam, spider-ball, and space jump helped her traverse the landscape and became staples of many Metroid titles to come. The games epic final battle made way for a turn as unlikely as the preceding game: a single Metroid hatchling joins Samus Aran as she leaves the planet.

Honorable Mention:
Super Mario Bros 2: Great game, but really just the US Doki Doki Panic. Drastically different from SMB1, but few elements repeated in future games. It was all a dream anyway.
Mega Man 2: More bosses, perfect music, and refined gameplay. Although one of the most popular in the series, its not significantly different from the one before it, or any of the hundred after.
Sonic 2: More fun than the first, which was already pretty fun! VS mode and co-op, new bonus stages, and the spin-dash! A refinement more than a revolution, but Sonic hasn’t been the same since the Genesis…