Patch 2.1.1 is a hotfix patch that fixes a few issues, some old and some that were introduced with the previous patch (2.1). The achievement "Heavy artillery" now displays the correct number of lasers fired needed in the tool tip. Bug where you would end up in the wrong world after pressing "Level Selection" in campaign mode has been fixed. It was introduced by the new "next level" button. The new enemy now has the correct spawn rate and should appear much more frequently.