If the consumer is being asked to "choose how much you want to pay" as they buy it, this sounds like commercial rather than non-commercial use. It is somewhat different, in practice, from a "donation" system where people can freely share or download your game and choose to go out of their way to donate if they feel like it.
I have a "semi-commercial" category in my Terms of Use that covers cases like the ones mentioned in this topic where you are not directly selling your game to people, but the game is intended to make you money in some way (microtransactions, promotion of a business, contests with $500+ prizes, etc.), and my semi-commercial licenses are very cheap. In my eyes your structure would definitely be a "semi-commercial" one but it's rare to find this kind of granularity in Terms of Use.
Since this is a relatively unusual structure, though, you should follow HIme's (and others') advice and check in with the individual artists/musicians/scripters to ask whether they consider such a use commercial, non-commercial, or otherwise. Where you can't contact the resource owner, assume that your project is commercial and follow the commercial rules.