The boss in FFX is not hard anyway, probably, because most of the bosses have a weak point (vulnerable to Silence, Provoke, Poison etc). The only boss that I have problem is Seymour, Evrae and Seymour Flux.

Shadow102, it's best to play it without GameShark, that way, you win it by yourself even if you check for some help in IGN, GameFAQ, GameSpot, FFOnline and other useful website.