When you run the game for the first time, The Legend of Zelda: Ocarina of Time 2D will detect if you have a joystick connected to the computer and let you configure it if you do (but it's also possible to play using a keyboard). In either case, as in the original game, you'll always see the controllers on screen.
Little to nothing can be said about the gameplay that any gamer wouldn't already know. The controls are practically identical to those in A Link to the Past, with a few lightly adapted elements for Ocarina of Time.
In few words, The Legend of Zelda: Ocarina of Time 2D (OoT2D) is the game you would have had if Nintendo had launched Ocarina of Time on Super Nintendo instead of Nintendo 64. In other words, one of those 'what ifs' that is well worth a good look.
This version of the game is still under development, so you can only play the beginning of the adventure.