@uknownada Both are correct and acceptable, from an origin perspective, Octopuses is more right (since it's Greek) but since octopi is so common and old it has become an acceptable variant.
@evgo7311, try holding z and pressing left or right. if you do it 3 or 4 times all goblins will be on one side, do this combo a couple of times and you can get them all hitting at the same time too.
glitches:
you have to kill units from top to bottom.
when you start a new game without refreshing, you keep your progress on the bank and hotels and when you conquer cities they already have the buildings you built the time before, meaning you can't earn money or get people.
when you conquer a city you no longer get income from the cities you already have.