It’s almost a guarantee that if you make it past round 12 which consists of sand elementals, gigazappers, and pirates that you get to round 16. Meanwhile round 11 tends to be the determining factor if you have a coordinated team or not, and from my perspective, is too much of a determining factor (similar to round 16). The progression in difficulty in rounds is too lopsided and is much more of a rollercoaster than an upwards progression.