As they mention in the overview for this game jam, each person will have their own interpretation of the theme and the limitation. For example, I'm going for the form of heaven where only angelic creatures exist that originally were created to live in heaven, totally separate from people who have died and gone to heaven as angels. Someone else was talking about using the mythological form of heaven, also significantly different from the form you are referring to. Up to you to change things around to create a new idea of death in heaven or do something similar to what I'm doing, which is having the rebellious angels cast to the abyss, where they will be exterminated.