Easiest way to complete...
	Gameplay strategy...
	Missing Treasure Items...

When upgrading your attributes or equipment (speed, stealth, grip / boots, amulet, bracelet respectively) choose grip till you've finished upleveling that aspect; the spirits are pretty tough to fight but tools to catch them in the first place are pretty easy to come by (speed sandwiches and stealth potions).

Search for spirits and their maps and pick paths that will enable you to ultimately indentify their specific path. Also use gear & Bombs for better game strategy. Make use of leveling up rewards to raise your main acceleration as well as stealth.

Although nearly all are in locked boxes either in the four areas or within houses in those four areas there are a couple of additional locations: one is down on the beach, the other is in te spaces or corridoors between locations (try mailmans house between Serfside and Splitwood). One area that eluded me for a while was behind the statues that carry the fish gods eyes in Rust Grove. Other than that, bash down every locked door and take the opportunity to walk around (rather than run) and see the areas you missed while chasing spirits.