Recommended ROM hacks

• Love Yourself (SNES) - 17-exit Kaizo Super Mario World hack that is widely considered to be a good starting point for new Kaizo players.
• Panga's Kaizo Kindergaten (For Dummies) (SNES) - A tutorial for Kaizo-style Super Mario World ROM hacks, implemented as a Super Mario World ROM hack.
• Pokémon Blue Kaizo (GB) - An intentionally punishing version of Pokémon Blue. All 151 Kanto Pokémon can be obtained through wild encounters or evolution. Trade evolutions are now obtainable via level up. Enemy trainers have different teams with better type coverage and more powerful movesets. Maps are modified to be harder to navigate and make many previously avoidable trainers unavoidable. Revive items can only be used outside of battle. This ROM hack demands absolute mechanical mastery of the Gen 1 games, and as such, I found it to be a very fresh experience.
• Pokémon Crystal Clear (GBC) - Significant overhaul to Pokémon Crystal that makes the entire game a huge sandbox. You can start in any Johto or Kanto city, and the game's trainers and gym leaders scale with the number of badges you have on hand. All 251 Pokémon can be obtained without trading.
• Super Metroid Arcade (SNES) - Super Metroid room randomizer with a run-based score system and slowly increasing difficulty, making it into an arcade game where you must complete as many rooms as possible.
• Tetris: Rosy Retrospection (GB) - Implements modern Tetris gameplay mechanics in the original Tetris for the Game Boy.