I noticed shrunken heads dropping during my first playthrough. I ended the game with somewhere close to 40 souls. There is a great recommendation using the Isla Cruse mission. It worked like a charm for me. It did take a while but I was watching football game so I wasn't really paying attention. I kept playing till the soul counter got to the high eighties - I accidentally killed the boss. Ended up having more than enough but I really didn't want to play this game anymore.
As far as the missed items - I went back through and picked up a couple of the ones I missed. I had to collect them all during the second playthrough to make the ach pop.
Good luck - I've played some bad games but this one is really high on my worst games ever list.
Started Using x360a.org - June 2008 - 3K Gamerscore
Hit 100,000 GS on 12/22/2011 with Mile High Club - thanks to all the boosters and this great site.
Looking to Boost: Halo ODST - Endure Only, Ghostbusters, Quantum of Solace, GTA IV Multiplayer, Halo Reach DLC
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