Cheats should be working in-game now; but they have had a slight key configuration change, similar to TY1, so that they work with KB&M as well.
The start sequence should be:
Left, Right, Action, Left, Right, Action
Then followed by the same keypresses as in the original release
Add Opals – Bite, Jump, Bite, Jump,
CollectableLocator – Up, Down, Left, Right,
AllLevel1Rangs – Bite, Throw, Bite, Throw,
AllLevel2Rangs – Throw, Bite, Throw, Action,
GetBunyipLicenses – Throw, Bite, Throw, Jump,
Note: That using cheats will not let you post to some leaderboards, or get some achievements.