Talk:Summer 2015 Event/@comment-110.77.161.218-20150817014132/@comment-25730832-20150817031244

Yes, you can revert back 2 difficulties. The requirement is that you have E-4 medium cleared if you want to 'try out' hard, not picking easy in E-5 and go to E-5 hard while not clearing the map yet.

As Lush said, ship-lock will go into effect once you go to hard and IMMEDIATELY after you sortie to E-5 easy so use ships that are already tagged from previous maps so that you don't waste any tag ships.