Pokemon Heartgold holds up quite well, but ultimately it's the little things that kept me from thinking this is a great game instead of just being good. The level curve is for example one thing that is often criticized, and I agree with that, but also the low variety of Pokemon until you reach Kanto, the slow battle system and the lack of some of the quality of life changes in modern Pokemon games. The sheer amount of content is incredible though, and it captures the feeling of the original games perfectly while still having some of the best sprite designs in the entire franchise.