Wow, what a necro-bump =)
I don't think I can vote on this one. I've beaten 1, 2, 4, 5; still working on 3; got bored of 6 halfway through, but I'd hardly consider it "worst game ever".
Only played the GBA version of 2, but I actually liked it a lot. I thought the "level your skills by using them" mechanic was a cool idea, if not poorly implemented. They could've fixed it with a third game, but like most #2 games, decided to just go back to the classic formula instead.
I didn't like 7 when it came out, but I feel like if I tried it again today, it wouldn't be such a jarring mess of "OMG do I seriously have to watch -another- cutscene???"
8 looked bad, none of my friends liked it. 9 might be okay. No interest in any games past that.
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I'll brave the storm to come, for it surely looks like rain...