Reader Michael Sterling pointed out today (or rather late last night) a neat tool that lets you create music even more easily than with Finale:

For people who want even easier music creation so are willing to give up some of the nuance that Finale offers, they could try It's kind of like GarageBand for the mac (I'm sure there's a non-apple analogy), but even a bit simpler. You just choose the instruments you want to use and then assign chords to each measure. They want you to sign up, and there's a little tutorial video that plays when you first start, but you can skip it and don't have to sign up (although you might need to if you want to export the music, I'm not sure)."

I took a look and it indeed looks pretty cool.  You can sign up for free, but to export an mp3 of your work requires a $10/month subscription.  Might be worth it if you create a bunch of songs, sign up for a month, then export everything at once for your game.  After playing with it a bit, it sounds like it’s using samples instead of midi for at least some of the instruments (which sounds a lot better although you lose the retro vibe) and is indeed super easy to use, even if you know little or nothing about music.