5 - Smash 64. It was impressive for the time, but now, it's just ok.
4 - Melee. Okay, okay, it's great and all, but's it's really ruined by the overwhelming competivie scene.
3 - 3DS/Wii U. Smash Run. Enough said.
2 - Ultimate. Lots and lots of stuff here. It's awesome.
1 - Brawl. Adventure...