Hello!
- Yes you can use them.
- Difficulty is debatable and it will be up to you as a developer to tackle that challenge!
- There are no strict rules in regards to pacing and or the type of game you make!
Also for @arthurfalaschi
There is a slight miscommunication and to reclarify, we do allow custom assets to be reused. If you have an old project that has script calls or old custom plugins, you can reuse them! The key rule is that the actual game development (maps, events, coding, etc.) must start during the jam period.