Walt in season 1 vs season 5

Near the beginning of season 1, Walt crosses a dangerous drug dealer and holds him captive so he doesn't come after Walt and his family. He just wants to set Krazy-8 free and not have to worry about him again, but is forced to kill him in self defense, apologizing profusely all the while with tears in his eyes. In the last episode of the series, it's as easy as pointing and clicking.

Example of:
Character Development