This is a side-scrolling action game.
Control him well and keep him alive.
He lives by the following rules.
When he breathes oxygen, he enters his initial state.
When he breathes hydrogen, he becomes lighter.
When he drinks water, he feels well enough to climb a hill.
Carbon monoxide is a poison to him.
Nitrogen monoxide is poisonous to him.
When he touches gold, he can survive.

No reflexes are required for this game.
However, it does require calm judgment and a little knowledge of chemistry.