So tell me you work for the Dev team without telling me you work for the Dev team.
Game developer release a patch which changes a game
When a developer creates a new version of a game (called patch or update), it contains all of the game files. So each patch can be downloaded separately to get the different playable versions of the full game.
When a new patch is available, the client downloads only those files which have been changed since the version the user currently has. For example if in the patch v1.01 only the game’s sounds have been changed and you already installed v1.0, then during patching your client will download only the sound files. On the other side someone who just bought the game will download the full v1.01 version with all of the files.
So a patch is just replacing files, which makes it totally possible for the developer to turn a strategy game into a racing game with a new patch. If the developer replaces the asset files (models, textures, icons, sounds, animations) then you get the same game which looks different. However if the executable files (exe, dll) were replaced then the game’s logic had been changed which makes it possible to get a new game mode, a new champion, new game balance, better graphics or a whole new game.