It's an easy game, which is very much a plus in game jams, and the music is really good too, the only things I'd say is that, as others said, the neutrons are also in the nucleus of the atom, the ones outside are the electrons lol.
And if you run out of neutrons you can't do much more than wait while lasers got in. I'd also say that the switch should be with the same key, if you can only switch from right to left and left to right then there's no use having separate keys for each switch.
Overall it's pretty good!