One small thing I've noticed, maybe a bug? The upgrades say +4 on some things, makes sense I guess, but when you decrease the level, especially in the modules, I don't think you get your full money back, or at least not after the first purchase, I bought a module for the server alerts, realised I didn't want it, so I sold the module and then I thought again "Ehh, actually, I'll keep it, I have enough credits" then noticed my credits were lower than when I FIRST bought it, the cost of the module still said 50, so I "experimented" a bit, purchasing the upgrade and then selling the upgrade over and over again, before you know it, I ended up with not enough credit to purchase it again, seems like the +4 stays with it, even with the modules, so you have to (If you ever sell modules and upgrades to purchase other stuff) sorta keep a record of how many times you've sold said module/upgrades so you know how much it actually costs, as the module still said 50 but not showing the +4 after I sold it and rebought it, so.... idk, maybe selling modules wont give you a full refund and this might be normal, but in case it's not, figured I'd mention it just in case (for the people who want to sell modules to afford other stuff)