Thank you for your comment and feedback!!
I'll be sure to add a warning when you're deleting upgraded items!
As for biofuel, in the full-game there will be auto-refilling biocells; as well as easier UI/UX where you can simply right-click and select to fill up biocells!
And noted on the lag! the fog on the map causes lag on browsers... I'll make sure to optimize the map further in the full game!
Again, thank you for your kind comment! glad you enjoyed the demo!