Sonic & Knuckles (World)

Sonic & Knuckles is a platformer for the SEGA Genesis, released in 1994 as the direct sequel to Sonic the Hedgehog 3. Developed by Sonic Team and published by Sega, it's the second half of the story that started in Sonic 3. The game is famous for its cartridge's lock-on technology, letting you attach it to Sonic 2 to play as Knuckles or to Sonic 3 to combine both into one huge adventure. That hardware trick made it unique on the system and still gets talked about today.

You take control of either Sonic or Knuckles (the latter can climb walls and glide). Levels are split into two acts each, with a boss fight at the end of the second act. The goal is to reach the goal plate while collecting rings, avoiding traps, and smashing enemies. Sonics spin dash and Knuckle's glide and climb give different approaches to the same stages. The lock-on feature also adds special zones: if you own Sonic 3, you can play the combined Sonic 3 & Knuckles campaign with all levels and a proper ending.

What makes Sonic & Knuckles worth trying today is that lock-on gimmick - no other Genesis game did that. The gameplay is classic speedy platforming with tight level design and memorable music from the Sonic 3 era. It's a must-play if you enjoyed Sonic 2 or Sonic 3, and the ability to combine cartridges gives a sense of discovery even now. It's held up well for a 90s platformer and remains a highlight of the Genesis library.