Sonic & Knuckles for Mega Drive
It’s fairly well known by now that Sonic 3 became such a huge project that it had to be split over two carts, with Sonic & Knuckles effectively serving as the “second half” of Sonic 3. As such, many of its innovations are carried over verbatim- new music and backgrounds per each Act of every Zone, levels that favour exploration and speedy play equally etc.- but it does have one major benefit by way of it’s Lock On technology. Not only does this allow players to connect Sonic 3 and Sonic & Knuckles together to get the complete Sonic 3 & Knuckles, but you can also attach Sonic 2 to the cart, allowing players to go through Sonic 2 as the eponymous rival. A truly ludicrous amount of bonus variations on the game’s Blue Sphere special stage can be fiddled with by connecting other Sega games, as a little easter egg!
Similarly to Sonic 3, Sonic & Knuckles is a fairly fun and engaging challenge even independent of it’s first half, and is worthy of owning as a standalone title in its own right.