Different from your usual tree this one is much slower on it's first two layers, there's no milestone mechanic on those layers so the game dont get faster till you get to like the 3+4 layers, but even then it's still away too slow taking hours to just unlock the 5+6 layer. And when you finally get to those layers like expected they reset the past ones. But here's the problem, usually a higher layer boost all layers bellow, but in this case it only boost the tier bellow not all bellow, meaning till you get enough currency on layer 1+2 to start getting currencies on layer 3+4 the boost you got from layers 5+6 dont mean anything. This was written before i started doing challenges or got the upgrades on tier 5+6 shop. edit: The challenges are what speed up the progress and some of the upgrades in layers 5+6, layer 7 furter speed the game with the research.