You're fine to have whatever rules you want of course, but perhaps a more useful rule would be "Does this game have enough content to justify its price?" regard

You're fine to have whatever rules you want of course, but perhaps a more useful rule would be "Does this game have enough content to justify its price?" regardless of its finished-ness. There are finished games for which that answer is "No" and there are unfinished games like this one for which the answer (IMO) is "Yes".