I was wondering the same thing! I no what kind of game I want to make but I'm not sure If I should learn as I go or strap down and learn things I dont even intend on using. So far though my prob is memorizing long lines of code though so I plan on spending more time practicing things I need.
Things you think you don't intend on using are the things you are neglecting to learn. You will be sorry when that thing makes your life easier programming the game. These things are built by programmers and for people using them because it works and saves you time. Why would you neglect learning it? It makes no sense.
You're not suppose to memorize code. That is pointless and a waste of brain cells. You are suppose to understand the principles, concepts and ideas behind what the code is saying. Treat programming like a story and you will say "Hey this code was well-written and I actually got something out of it!" Programming is not a memory game.