Topoisomerase is a goup of enzymes responsible for untying knots and twists on DNA strands that appear after processes like replication. In this simulator, you would play the role of a topoisomerase and solve topological puzzles before the DNA strand turns into a big mess and your cell dies.
References:
https://www.youtube.com/watch?v=UkmQNbvlK8s
https://www.youtube.com/watch?v=HyP0cEbqKTc