Based on an Apocalocke run I did of Pokemon Fire Red in 2017. The rules are simple:
1. Can only catch the first Pokemon on each route.
2. If a Pokemon faints, it's dead.
3. Every Pokemon must be nicknamed.
And because it's an Apocalocke, the scenario I got was a drought so that limits the Pokemon I could catch to Normal, Fire, Electric, Rock and Ground types. Gift Pokemon are still okay though!
The story follows Vivor who is sent on a quest to try and restore order to the Kanto region which has fallen into madness after a massive drought.