Just because blockland has blood in it won't make it M+. Its vitural/fake looking blood. It just looks like a little dust cloud of blood. I would find it still E+ but if anything maybe 10+. I mean come on, you are made out of blood, you fall and hurt yourself you bleed, you die from getting run over, you bleed no?
People these days are too sensitive over things like this, I honestly don't think any parent would find the blood dust clouds inappropriate.