Is this something that can be used again and again? Or is it 1-2 times and then done?

Yes and no. It comes with two pods and once those are used up, you're left with a set of beakers, mixing spoon, and center "reactor ". You could fill the center reactor with baking soda and then use the plungers to push vinegar inside. Or you could put a bathbomb in the reactor. Or if you have food coloring, you can color your water and then plunge in to mix. Of course, you can do all of these without this kit.

Are the creatures based on actual germs or chemicals or just make believe? Would like something with a little bit of real world application.

Hello Amazon Customer! The Reactor Super Lab comes with instructions needed to perform amazing real-world science experiments inspired by the creatures and their home planets. instructions needed to perform amazing real-world science experiments inspired by the creatures and their home planets.

I know the kit comes with 2 reactor pods, but can you order more separately?

Yes you can. 6-pack $28.99 amazon prime

Is this intended for use by 2 children or 1?

Hello Amazon customer! The Beaker Creature Reactor Lab is intended for one user, although multiple reactor pods can be used which would allow for additional use. Feel free to contact us at review@learningresources.com with any other questions you may have.