By mistake I played this one after KH2 so sadly my opinion is skewed. This game is great, don't even doubt that for a moment. However, it shows age in some parts of it. The HD collections largely work to fix this, specifically with menuing, so it is still very beginner friendly.

The amount of times I hear "There's no way you're taking Kairi's Heart" per playthrough is mind-numbing but that entire scene has such impact. It's the pivotal moment when Sora accepts his role as the Keyblade Master (oh you poor sweet summer child) and does the right thing.