I finished Final Fantasy XIII, I bought it on the day of release. One of the problems is that it requires "finishing" the game (beating the final boss) before you can unlock the maximum abilities and therefore easily explore the open area and gather everything. Even when fully buffed up it takes some tricks to beat certain enemies like whatever the name of the most powerful giant-tortoise-thingy was. Getting platinum from that thing is the only good way I know of to get money in that game so it's rather painstaking. The combat system is very flawed, the way it requires building up, that way you can't really ever 1 hit kill anything yet they managed to make it fast paced enough that it actually is fun.
You know what, I think I will go back and finish collecting everything. Part of the reason I never did that is because it overall left a bitter taste in my mouth. They canceled the PC version just months before release apparently and even worse the entire game/story was allegedly downsized/crippled to accommodate Microsoft and to make more profit by selling it as two games. Apparently Microsoft demanded that it doesn't take up too many DVDs, I don't know why they did that... FF13 had no real towns, just a linear run for and to complete the story there will be a part 2 released in 2012.
Considering a lot of FF games are among my favourite games (13 included) as you can imagine I was furious that the game was split and the PC version canceled. Perhaps if I was younger I wouldn't care but the low resolution, frame rate, heavy aliasing and the weird scanlines they use in a poor attempt to mask the flaws drive me insane. Especially the heavily scanlined hair, makes me foam at the mouth in rage, I'd rather see the low resolution hair than have to see that nonsense.