Blockworld – The final secret planet in Solar Smash is called Blockworld. This Solar Smash secret planet is reminiscent of Minecraft, and is most likely a callback to the classic voxel game. To unlock the Blockworld secret planet, the Cube Earth secret planet must be unlocked first (shown above).
How do you get flat Earth in solar Smash?
All Secret Planets & Easter Eggs | Solar Smash *UPDATED* Tutorial (2022)
Flat Earth – 
Flat earthers rejoice, Solar Smash has a secret planet called Flat Earth which can be unlocked. In order to unlock flat earth, simply set the laser to “5” and use it to get rid of the upper and lower parts of the planet. When only the middle part is left, hit the reset button and you’ll get Flat Earth as a target.
