ill give some ideas:
1: add an option to upgrade by 1s,10s,100s, or adjustable.
2: display messages depending on how many of a resource you have
3: option to prevent getting a negative amount of resources
4: maybe add a option so you can have a bit of ad space
5: sacrificing an amount of resource/ everything you have to get a different recource. (like cookie clicker heavenly chips)
6: able to encrypt the url or something so people cant go poking around in data files you spent a long time on
7: maybe an offline version of IGM. like a downloadable where you can download pastebin files on the internet to play offline or use a txt file on your computer to stop annoying beta testing where you must: test, change pastebin, repeat infinite times. this really gets on newbie's nerves.
8: make a certain website (by you, orteil) where you can upload your txt's (either copy-paste, write in there or use an existing txt file on computer) and can upload pictures (keep unused areas) you can use in your idle games.
9: able to scale pixel art. I beg you, orteil