You can always turn off whatever feature is blocking you from saving your worlds. Like if you have it clear cookies when you close your browser or something. I hope you find the culprit!
Great game.Though, I feel like maybe a few things are missing. (Examples: the abandoned mineshafts being underground, villages and npcs, and texture pack compatibility, and less glitchy squids) But overall, BEST MINECRAFT FANGAME EVER!
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You can always turn off whatever feature is blocking you from saving your worlds. Like if you have it clear cookies when you close your browser or something. I hope you find the culprit!