The flash back made me cry. It feels so good to watch this. It may be soppy, but hey. Charmander was close to Ash before, and they grew close again. It shows how even though people important to you can grow apart, you should never forget the great times you had, and it may never be too late to make amends.
The scenes with Ash defrosting Charizard were so touching and I was relieved when Charizard trusted Ash again and when he defeated Poliwrath.