The legal section of the README, in the first paragraph, states that Devilutation is supposedly Public Domain, but then in the subsequent paragraph goes to impose a non-commercial use clause. Those two seem to contradict each other, since "Public Domain" by definition allows use for absolutely any purpose, including for-profit. I don't know whether it's legally possible to "remove" a work from the public domain, but in either case it isn't entirely clear what the license is supposed to allow.
The legal section of the README, in the first paragraph, states that Devilutation is supposedly Public Domain, but then in the subsequent paragraph goes to impose a non-commercial use clause. Those two seem to contradict each other, since "Public Domain" by definition allows use for absolutely any purpose, including for-profit. I don't know whether it's legally possible to "remove" a work from the public domain, but in either case it isn't entirely clear what the license is supposed to allow.