It's not bad, but it has a few issues. Mainly the user experience. First, you have to think like a lot, you have a lot of resources and you have to pay a bit of attention to every single one to balance out the input and output so you won't get any bottlenecks or a red numbers. There are a lot of forumlas, and formulas of formulas and formulas of formulas of formulas, it becomes a bit convoluted (I just woke up, probably my brain is not at 100% yet). Then the way items are sold is a bit weird and unintuitive. Mabe instead of a checkbox a few buttons could be better, and "sell all/sell half" buttons too, because if you need cash you just have to check/uncheck every single item. The knowledge, I don't know if it's useful after you buy all the upgrades. Oh, and BTW, it took me a while to realize you can pause/resume production by clicking the green circle. Edit: AND I finally managed to get 5k/5k on both resources at the T5 Catalyst Crystal but I can't find anything to do with it, clicking the image does nothing and there's no new button on sight. But it's not a bad game, but the UI is the main problem, it's not very intuitive in many cases. Still, it's simple and good enough to have on a second monitor while you do other stuff.