There are other terms, like "affection points" (a slightly different system) which are easy to understand, but "flags" is at least as common as any of those.
What is the reasoning behind the terminology "flag" in this context and where does it originate?
The money will go to our team members beside kickstarter fee and the rewards.
The term "flag" doesn't seem particularly romantic or descriptive in this context.
We are a startup game developer team from Indonesia with focus to game with artistic contents (for now).
Our main goal is to introduce the potential of Indonesian creative industry to the world, but for now we just want to do experiment on some small projects. RCz - Character Illustrator Athin - Game Designer Ombobon - Background Illustrator Jun-P - CG Illustrator Phi Quadrat - Lead Programmer, UI Designer Rizki ARM - Programmer, Consultant Bonita Bone - Item Illustrator, Programmer Reef Meizer - Chibi Illustrator Donsaid - Background Illustrator Vesuvia (Ecky) - Music Composer Novalia - Translator Prima Mustika - Public Relations Rudychan - Producer Basically we just need some money to finish the development time of around 2-3 more months from now.
For instance, the manga The World God Only Knows (a parody of the dating sim genre of games) uses the term frequently, and the manga chapters are numbered as flags (e.g "flag 53").
I've seen it in many other anime and manga as well, both in Japanese and translated into English.