Incredible base game.
Gen 1 was a badly designed mess even on the 2nd try, they were still learning.
Gen 2 was greatly improved, but still shackled too strongly to Gen 1.
Gen 3 they started to finally get into designing the games well, and refining mechanics.
Gen 4 they brought it all together and created the best core Pokemon game they've ever made.
There really hasn't been any big innovations in the game since Gen 4, just expanding on the already existing mechanics and adding and dropping gimmicks.
