20. Describe a mechanic you would put into your Science Fiction Heartbreaker.
Oh, maybe you mean a game mechanism...
There are a lot of ideas that have already been incorporated into science fiction games over the years. But most of them are generally ignored during the course of play...so I guess the question is what I'd make sure appeared in a heartbreaker, and what the definition of a heartbreaker is. One of the many definitions of a heartbreaker is the kind of game that basically replicates an existing game, but renames a variety of elements and adds one or two specific twists to the game mechanisms to claim the game as "original". The whole of the OSR is basically heartbreakers.
What are we trying to emulate with this game? What type of science fiction?
If we have multiple races, I'd want to make sure they were alien and exotic to each other. Roleplaying to me is about getting into alternate thought patterns to explore ideas outside your regular identity and paradigm. I like the idea of paths of enlightenment in the Sabbat books from Vampire: the Masquerade. They are designed to be ways that control behaviour outside a humanistic paradigm. Some have similarity to humanity, many are very different. So I'd throw a few paths like this into the game, requiring non-humans to follow one of them as a reflection of their different mind-set. Maybe a single path per alien race, but probably a few related paths for each alien race (and a few similar paths for humans to choose from).
For truly different racial perspectives, I'd limit in-game speech to a word or two between characters at most. Only those who share ideals and agendas would have enough commonality in their thought patterns to meaningfully communicate with each other.