Well, your custom sandboxes are a collection of gases and liquid substances, right? All these substances are very realistic. It's funny when oil begins flying (It looks like burning and becomes a gases). You should make the oil change it's color when thouches fire. Oh and fire should be more realistic. it could be good if you will do a mercury. And, are you going to make any element in solid state like aluminium, lead, tin or polon? It could be great!
Oh, I thought you will never make any situation critical! But you did it! This is great and I hope you'll make more!!! Oh and I have an idea for new situation critical! An agressive dinosaurs are chasing you and you must not be catched by them and escape using a train or car!