Planets fall from the top of the screen, and when two identical ones touch they fuse into a larger world. Drop Planets is a merge puzzle about keeping that growing pile under control, because if it rises past the danger line, the whole galaxy collapses.
On a computer, the arrow keys move the planet into position, Space releases it, R restarts and P pauses. On a phone, hold and slide your finger, then lift it to drop.
Next to a planet of the same kind. They merge as soon as they touch, which frees up room in the stack.
Yes. As you level up, the galaxy grows, the danger line creeps higher and rarer planets start appearing in your hand. Those who prefer merging numbers instead of planets can open 2048 Classic.