Not a bad incremental, but could do with some polish. The UI is a bit of a mess for a start. I'd love to see options to turn off the floating text every time one of the machines do something. Further upgrades like the ability to overclock more than one machine at a time for example.
I also know that you Game Over if the room overheats too much, but I've no idea at which point. I have no reference point when it comes to Farenheit, but I suppose it might be too much to ask that you'd add a Celsius conversion.