The best Pokemon fangame, and better than some of the Pokemons. The fusions are incredible. There are something like 76k possible Mons to get. There is a built-in randomizer for a fresh playthrough each time, and there is a game mode where you can have it be themed around one Pokemon. Sound boring? Remember: even just limited to one Pokemon, there is still a ton of possibilities.
The engine it is running on in pretty janky, unfortunately.