Not really a game suggestion but here it is anyways.
Having implemented a bunch of different payment api's and seeing that you are using paypal as your primary donation portal I thought I would throw out a couple of potentially better options that would get rid of fees, make it easier to make donations/receive payments and allow more currencies.
Square is a zero fee(so long as you are not a business) payment gateway that allows people to pay you via an email, phone number or directly on a personal cash.me (mine: https://cash.me/$tmain)
The other one I would recommend would be Coinbase(https://www.coinbase.com/?locale=en) This one would allow you to easily collect bitcoin donations, I dont think they charge anything to convert the bitcoin to USD but I cannot remember for sure. Alternately even if you just have a bitcoin wallet sharing it would allow you to receive bitcoin as donations.
Fees are annoying. I will totally be the first to make a bitcoin donation if you go that route. If you want/need any help with either I would be happy to help also.
Anyways, just a thought.