  Using three years of game data of the online collectible card game
Hearthstone, we analyse the evolution of the game's system over the period
2016--2019. By considering the frequencies that archetypes are played, and
their corresponding win-rates, we are able to provide narratives of the
system-wide changes that have occurred over time, and player reactions to them.
Applying the archetype frequencies to analyse the system's Shannon entropy, we
characterise the salient features of the time series of player choice. Paying
particular attention to how entropy is affected during periods of both small
and large-scale change, we are able to demonstrate the effects of increased
player experimentation before popular decks and tactics emerge. Furthermore,
constructing conditional probabilities that simulate understandable player
behaviour, we analyse the system's information storage and test the
explain-ability of current player choice based on previous decision-making.
