Final Fantasy 10?

Once you collect his celestial weapon (the Caladbolg) you will be able to break the damage limit with him - you'll need to have the celestial mirror, then search the northwest corner of the Calm Lands, behind a mandala at the bottom of a very narrow hidden trail. Win all four chocobo races, and the person blocking the pathway will be gone. You can also search out the Sun Crest and Sun Sigil to upgrade the weapon... with these it becomes Tidus's ultimate weapon - [Break Damage Limit] + [Triple Overdrive] + [Evade & Counter] + [Magic Counter]

Good luck!

Edit: Yeah, you'll need those two. After you get them, the No AP will be replaced by the Triple Overdrive.

Well, I don't know which version you are playing. It's either the original or international. All of the Celestial Weapons for the characters have Break Damage Limit. They are the best in the game. However, you can also "Customize" a weapon with an available slot to have the Break Damage Limit Ability. Getting the Caladbolg for Tidus isn't the only way although its much favorable to get. You need 60 Dark Matters if you want to customize a weapon to have that ability. Problem is, I think that it will take much more time, effort and luck in achieving such a task (capturing monsters etc.) and I can't really guarantee it exists on the original version (played it a long time ago and the international version). Its easier to just get the Celestial Weapon.

In order to break the damage limit, you need Tidus' ultimate weapon, the Calaborg. Here's the guide to ultimate weapons

FF10 is pretty linear like 13, the battle system is different though, it's turn-based; kinda pokemonish/paper marioish cept you control multiple people. But besides that, it's basically the same cept older. If you're looking for something more open-ended you should look at FF12 (which has real-time on map combat) or try 10-2 (Traditional FF Combat) (Which some people can't stand because of the not-dark at all childish storyline and characters),