Modal Logics of Sabotage Revisited Guillaume Aucher, Johan van Benthem and Davide Grossi Abstract: Sabotage modal logic was proposed in 2003 as a format for analyzing games that modify the graphs they are played on. We investigate some model-theoretic and proof-theoretic aspects of sabotage modal logic, which has largely come to be viewed as an early dynamic logic of graph change. Our first contribution is a characterization theorem for sabotage modal logic as a fragment of first-order logic which is invariant with respect to a natural notion of ‘sabotage bisimulation’. Our second contribution is a sound and complete tableau method for analyzing reasoning in sabotage modal logic. Finally, we identify and briefly explore a number of open research problems concerning sabotage modal logic that illuminate its complexity, placing it within the current landscape of modal logics that analyze model update (including new `stepwise' variants of dynamic-epistemic logics), and, returning to the original motivation of sabotage, fixed-point logics for network games. Note: This is an extended version of a paper presented at LORI Taipei 2015, which will appear in the "Knowledge and Rationality" subseries of "Synthese". Keywords: sabotage game, graph games, modal logic, model change, complexity, dynamic-epistemic logic