Game Saves After completion of each level

That's true although it depends on intentions. My approach is to always create a unique and timestamped log file. The other is to append. Both ways are 'logrotateable'. I prefer separate files which require less parsing but as I said, whatever makes your boat floating :)

I think I know why: it’s because the small modules philosophy favours library authors (like Sindre) at the ultimate expense of library users.

Form validation is hard. That's why there are so many different form handling libraries for the popular web frameworks. It's usually not something that is built-it, because everyone has a different need and there is no one-fit-all solution.