To beat each stage, destroy all the blocks. Eventually you will be forced to destroy the "Core". To instantly move on to the next "Core", destroy the current "Core". Destroying the "Core" too soon isn't always the best choice as you won't have money built up to upgrade. Game Instructions:
To Move Left or Right Press the A and D Keys or use your Left and Right Arrow Keys. To Aim use your Mouse and to Fire Left-Click your Mouse.