I know this is not as impressive as some other projects here, but I would very much appreciate your feedback. Is it easy to use? If not, what should be changed

I know this is not as impressive as some other projects here, but I would very much appreciate your feedback. Is it easy to use? If not, what should be changed/improved? Some feature to add (or remove)? Is the code ok? Should I refactor some parts (and why)? Thank you in advance.