You can get keys by selling foods at Space Burger.
So, how about CONVERTING scores and medals to key?
here are how it works.
this feature is available at tier 99.
this feature can be done at Heroes Academy Campus.
Adding up ALL of your score and medals collected, you can earn keys, as many as your score and medals.
your tier resets to 1, and your medal and score do to 0 too. so some missions become unavailable.
note: some types of medal like contents contribution, early access participation, and galaxy 100% exploration reward medal CANNOT BE SOLD.
Don’t worry. your total play time, last connected time, your belongings DO NOT reset. ONLY MEDALS and SCORE reset.
If you play Weekly Challenges, expect 60+ hours of play time to recover to tier 99. But I’m still somewhat against this idea, unless there are exceptions for very important medals like 100% galaxy exploration, Early Access Participation, contribution medals.
I think once you have reached tier 99, you should already be able to buy all Always On items, some extra spacecrafts and max out some weapons… so I don’t need any more keys than that (unless you really want to go for that 100,000 keys).
Or maybe you could get 1 key for each earned medal on missions.
At first glance it may sound like it’s not enough, but more experienced players usually get a ton of medals - no overheat, no deaths, 90% food collection, 90% of chickens killed, no special weapons, no satellites, no collected atomic powerups perhaps, completed mission type (trivial - elite) and more. Not to mention you can get some of these multiple times.