Fuse atoms and grow your nucleus! An atom will appear in the middle of your nucleus. Click on an empty circle to place the atom there. Regular atoms will contain their chemical symbol and atomic number. There's a special atom called the Fusion Atom; this one is red with a white symbol. Place this between two identical atoms OR two atoms that are 1 atomic number apart to fuse them, which will change the atom's chemical symbol and increase its atomic number!

Each fusion gives your reactor energy and earns you Radioactive Coins. The more energy your reactor has, the more points you'll earn. You can spend coins by clicking on the Upgrade button in the upper left corner of the screen where you can purchase upgrades such as earning more coins per fusion, reducing the energy that drains per second, and much, much more!

You can see which atom will appear next in the bottom right corner of the screen. Every few fusions, your nucleus will grow and give you more spaces to place and fuse atoms.

When your nucleus becomes full, the game will end. At the end of each game, you'll earn more Radioactive Coins based on how many atoms you created.

Unstable Nuclear Reactor Game Modes

Survival

This is the standard mode that follows the rules above. Each match you make charges the reactor but then the energy will slowly decrease over time back to the baseline.

Relax

The reactor's energy does not decrease over time; there's no need to rush. If you are looking for a more relaxing experience, this is the mode for you.

Orbital Survival Mode

Similar to Survival, but the nucleus is a perfect circle with fewer spaces to use.