Most upgrades can only be bought once, but some are '''iterative'''. Iterative upgrades usually become available after the player has bought 200 of one colony type. Afterwards, they can be purchased once per 25 new colonies.
The player unlocks new bacteria upgrades by purchasing more colonies. After purchase,
bacteria upgrades cannot be sold or disabled.
The ''Buy all upgrades'' option is unlocked after the player has destroyed 6 [[Planets|planets]].