I've been asked to add some way to donate, so here is a link to Paypal Donate.

Disclaimer: I will do anything I want with the money and you will not get it back. However, as an unquestionable fact, donations will hugely improve my motivation for making this game. As of 9th April 2011, I've got around $30.

That button reads "Donate" only because that is the default text of the Paypal Donate button. It doesn't ask you to donate, and you don't have to donate. I received many comments from people who somehow got very scared thinking this is illegal fundraising according to the finnish law. It is not. It is not fundraising in the first place. You could see it as a parallel to putting your bank account number on a web page, so that you won't have to always tell it to everybody in person.