The project is currently open for backers with credits. You can't add anything to your pledge because you don't have any.
Project overview
Pledge manager and late pledges no longer available.
If you're in Europe, you can now pre-order the English retail version below
Want more info? Click here to see the original Kickstarter page: https://www.kickstarter.com/projects/fromthewoodsstudio/explorers-of-the-woodlands