FFX was not only one of my favorite Final Fantasy games, but also one of the most amazing PS2 experiences. I picked up the remaster years ago, but had stopped part way through the game due to obligations at the time. I picked it back up recently and am hooked.
The HD remaster gets rid of any blocky, pixilated graphics and adds some international version features that are not apparent until mid to late game. The expanded sphere grid and addition of dark aeons to defeat change the end game strategy quite a bit.
Years ago, I had written off the celestial weapons for each character after frustration with the chocobo racing, butterfly chasing, and lightning dodging, thinking all three were ridiculous in difficulty and not necessary to defeat Sin. With the changes in end game enemies, I went back and defeated all three this week. I got the 0.0.0 time on the racing, completed both butterfly catcher trials, and dodged 215 consecutive lightning bolts to get the Onion Knight weapon! Now I just need to play about a month's worth of Blitzball to get Wakka's weapon and overdrive abilities!