TIC-80 is open source (however there is also "pro version" which isn't). "Regular", open source version supports editing only in built-in editor, no external te

TIC-80 is open source (however there is also "pro version" which isn't). "Regular", open source version supports editing only in built-in editor, no external text files. Update: seems that "pro" version is built from the same MIT licensed source, only prebuilt binaries on releases page is "non-pro". So it's completely open source.