Ringworld: Revenge of the Patriarch and Return to Ringworld are two adventure games set in Known Space, published by Tsunami Media in 1993 and 1994 respectively. Broadly, they concern events some 20 years after the novel Ringworld, so contemporary with The Ringworld Engineers; Louis Wu and Chmeee have disappeared, and the protagonist Quinn travels to Ringworld in a ship built by a UN-Kzinti project to implement a quantum II hyperdrive.
To what extent was Larry Niven involved with determining the plots of these games, and should they be considered canon? I am particularly curious because the ending of "Return to Ringworld" seems to reveal
the existence of a second Ringworld. Big if true!