Here is the detailed changelog for v0.64 to v0.66:
–new role: the game master (shortcut: F6). He can create new objects (mine, obstacle, rocks…) or enemies (sharks, submarine) on the fly to annoy the submarine crew! He can also freely move around and zoom/unzoom on the map.
-gameplay: accessing the bridge is now done with ESCAPE instead of F5
-gameplay: captain now has access to submarine oxygen, fuel and integrity
-gameplay: radio player can now mark an enemy if he identifies its frequency. Marked enemies are visible even in the dark.
-gameplay: new type of torpedo for the gunner: one which produces light (FL torpedo for “FLare”)
-level: tutorial is slightly easier
-graphics: captain colors are now yellow, other colors slightly changed
-graphics: obstacles and rocks assets have been improved
-graphics: new object: algae and rocks which light a little bit the abyss (thanks burgzaza!)
–new role: the spectator (shortcut: F5). He can watch over the should of any other role, and even watch the four other roles in the same time!
-gameplay: improved how torpedoes are working, with guided torpedoes
-gameplay: radio player switch from normal view to radio view by unzooming the view (instead of switching using space)
-gameplay: torpedoes now explode after a certain amount of time
-level: new level, the tutoriel
-graphics: when health is low, screen becomes red / flashing red
-graphics: when submarine is hit, lights turn off during about 1 second
-graphics: improved help appearance (looks to be inside the main screen)