When you start the adventure, you are closed inside a room with a strange alien creature that you can't inflict damage on. This is just the beginning of a story in which almost the entire city will be trying to kill your character.
The combat system, as in most roguelikes, is turn-based. You can move freely throughout the city tile by tile, going inside buildings, dodging vehicles, facing all types of enemies, and of course using lots of different weapons.
Rogue City Scavenger is a super-complicated RPG that you will possibly have to start over several times. Fortunately, as soon as you advance in the story, it starts getting more and more interesting.