Thanks for playing, and sorry to hear that! The goal is to complete the conditions in each level (they are shown at the start of the level, or when you press pause). If you manage to clear the conditions/kill order on each level of a loop in one run, you can get to the next loop, else you start over. For example, if you clear all the conditions in levels 1, 2 and 3, after level 3 you go to level 4. But if you mess up the kill-order in one of the levels, after level 3 you start over on level 1 again, until you get it right. This also allows you to 'power-up' before going on to the next loop ;)