I think there it would be the same as with kickstarter -> so in your case I think that you dont have to pay the 5% because the players can also get your game without donating to you
** What if my product obtains crowdfunding via Kickstarter or another source?**
Royalties are due on revenue from Kickstarter or other crowdfunding sources when the revenue is actually attributable to your product, for example if the user is required to purchase a particular funding package to obtain access (now or later) to your product, or if that package gives the buyer benefits within the product such as in-game items or virtual currency.
Here’s an example of what we mean by “attributable”: Assume you provide two tiers of offers, a signed poster for $20, and a signed poster plus game access for $50. No royalties are due on ancillary products like posters, so no royalty is due on the $20 tier. On the $50 tier, the user is paying for the poster with a $20 value, and that implies that the remaining $30 of value is attributable to the product. So, for each $50 tier sale, you’d pay a royalty of $1.50 (5% of $30).
Edit: you are too fast 