Chess opening are so complex and theoretical that amateur players will have trouble understanding them. An example is the Perenyi Attack of the Sicilian Defense (see diagram) which yields an immensely complicated and tactical position that even strong players have difficulty handling, and that is beyond the comprehension of most amateurs. Major changes in the rules of chess in the late fifteenth century increased the speed of the game, consequently emphasizing the importance of opening study. Thus, early chess books, such as the 1497 text of Luis Ramirez de Lucena, present opening analysis, as does Pedro Damiano (1512), and Ruy López de
Tactical role-playing game action role-playing game, real-time tactical RPG, survival horror and third-person tactical shooter elements. "Dead State" (2014) is a turn-based RPG developed by DoubleBear Productions and Iron Tower Studios set in a zombie apocalypse scenario. Players are tasked with leading a group of survivors living in a shelter in the fictional town of Splendid, Texas. "Dead State" mixes tactical combat and RPG character development with survival horror and base management elements. An "enhanced edition" was released in 2015 under the name, "Dead State: Reanimated". A number of "full-fledged" computer role-playing games could also be described as having "tactical combat". Examples from