Post early designs of characters, levels or concept art of cut features in video games.
Then, try to imagine how the gameplay would change if those designs made the cut for the final version of the game.
I'll start with the first sketch for Sora.
I imagine he would've been much more agile, with either a "switch mode" or perhaps simply his default animations, being more animal-like in nature, being able to dash around on all fours.
The car tire chainsaw blade would've worked similiarly to how the keyblade works in the finished game, only you keep doing damage if you hold down X, letting the rubber spin.
Perhaps a system could've been implemented where if you chainsawed a heartless long enough you'd get some sort of bonus damage buff for your next attacks, creating a combat flow revolving around holding down attacks rather than mashing them.