These Three Worlds by Burn the Curtain

The city is deserted but dangerous. Everything has changed, and strange new challenges wait around every corner. Ominous bubblings come from the river, howling noises can be heard by the cathedral, and the pigeons are angry. A bizarre new world is emerging from beneath the pavements of Exeter
Very few are brave enough to venture out onto the streets, but you have a job to do. A box of essential medical supplies needs to be delivered to the hospital across town, and there is no one else who can do it, so get on your trusty bike and start pedalling...