Do realise that, while games like Watch Dogs are designed to handle large, static scenes along with a relatively small amount of complex, dynamic shapes, Blockland is meant to handle (generally) up to 256,000 non-static, non-persistent, potentially complex brick shapes at once, along with however many players, vehicles, items, etc. that need to be rendered. Consider turning shader settings down on larger builds or lowering your draw distance in the advanced options. Lowering draw distance will also increase shadow sharpness.