Currently, when the next boss is to be fought, we craft an item an they spawn where ever we use it. What if instead each boss has a dedicated planet where either the item must be made or at the very least used ? So the existing bosses would work as such for example: Tier 1: craft an emergency receiver on your starting planet. Using it gets a fake distress signal giving the location of a penguin pirate colony which you raid for a molten core. Tier 2: when the mk 2 map upgrade is used, a special factory planet bookmark is added, where there is a special factory which you use to manufacture the robot( also removing the wonky logic that this boss normally had) Tier 3: mk 3 map gives you a castle world where you must deploy your decoy princess. Tier 4: mk 4 map gives you a slime/water world where you deploy the cunning trap Etc. This way we can have boss arenas for the sector bosses without worrying bout it not spawning enough as they use a pseudo coordinate book mark and since you gain the location bookmark when you enter each sector beyond the first, it doesn't allow for cheesing it through. I also assume that each boss area would have similar protection like that of dungeons except it can't be broken.