What was different about the Inca's religious beliefs from the Maya and Aztecs?

The three cultures had a lot of similarities in their religion: they're all polytheistic and many of their deities are similar, since their Gods are related to nature (Sun, rain, etc). A further similarity was a ritual human sacrifice.

The differences were more in rituals (the Inca for example sometimes sacrificed people by letting them freeze, while the Aztec killed them with a knife, because blood shed was the crucial part)