TY the Tasmanian Tiger

Completing 100% of the game means you need to complete every mission in every zone, complete every mini-game in the Danger Zone, Time Attack, and Turkey Chase categories, and collect every collectible in the normal levels.

Each normal level has 3 purple fruits (called Gooboo Berries), 2 koala bears, and 1 Thunder Egg to collect. The Gooboo Berries and koala bears are often found in hidden, or hard to reach places. To get to them, you need to solve puzzles, and backtrack often. The Cryptorang is also essential to collecting the Gooboo Berries and koala bears, as often they seem unreachable. The Cryptorang, when equipped, allows you to see hidden platforms that often lead you to these collectibles. For this reason, I always have the Cryptorang equipped, unless one of the elemental rangs are required to get past a certain objective. The Cryptorang can be purchased from the rang store on the main menu for real currency or for 7,500 opals. I recommend going the opal route since this is one of the cheapest rangs and the most useful. Since it costs 7,500 opals, you will miss some of the collectibles in the early levels, but you can always revisit them via the main menu, so don't worry if you miss some in the early goings.

As for the Thunder Egg in each level, it is gained by completing a secondary quest for an NPC. They will appear somewhere in the mission with an exclamation mark over their head, and after talking to them, will give you a secondary objective to complete in the level. Upon meeting the requirements, you will receive the collectible Thunder Egg.

Refer to the Zone A, B, C achievements on what is required to beat those specific zones.