  We review disruptive innovations introduced in the RoboCup 2D Soccer
Simulation League over the twenty years since its inception, and trace the
progress of our champion team (Gliders). We conjecture that the League has been
developing as an ecosystem shaped by diverse approaches taken by participating
teams, increasing in its overall complexity. A common feature is that different
champion teams succeeded in finding a way to decompose the enormous
search-space of possible single- and multi-agent behaviours, by automating the
exploration of the problem space with various techniques which accelerated the
software development efforts. These methods included interactive debugging,
machine learning, automated planning, and opponent modelling. The winning
approach developed by Gliders is centred on human-based evolutionary
computation which optimised several components such as an action-dependent
evaluation function, dynamic tactics with Voronoi diagrams, information
dynamics, and bio-inspired collective behaviour.
