Fissionary - Full Version

!!FULL VERSION!!

Want to try it first? Play the free demo.

What does the full version add?

Take your experiments beyond the demo’s tier-two upgrades:

• Complete research trees — unlock higher-tier particle, reactor, and machine upgrades.
• Active skills — unlock and upgrade Coolant Injection, Gravity Burst, Electrical Burst, and Overdrive to influence your reactions.
• Mobile matter vacuums — automate collection across your growing reaction, with movement, reach, and suction upgrades.
• Residue vacuums — unlock dedicated collectors and upgrades to help manage buildup and keep reactions running longer.

Explore more combinations, develop stronger builds, and push your reactor further.

One spark. A growing chain reaction. How far can you take it?

Fissionary is a particle-reaction sandbox about experimentation, upgrades, and spectacular chain reactions.

Choose your starting particles, ignite your experiment, and watch your build come alive. Collect the matter it produces, research new possibilities, and discover how different combinations behave.

More growth means more to manage. Heat, cold, and accumulating residue can turn a promising experiment into a catastrophe.

Experiment your way

• Discover eight particle types, each with its own role in your reaction.
• Choose your build and reaction controls to explore different combinations.
• Collect matter and buy upgrades that change how your experiments develop.
• Unlock matter vacuums to help with collection.
• Watch neon particles, electrical arcs, and reaction effects bring your chamber to life.

Help shape Fissionary

This is my first game as a solo developer, and I’d love to hear how your experiments go.

Found a bug or a performance issue? Leave a comment with what happened, your computer specifications, and a screenshot if possible.

Thank you for playing.