7: Load HTML Elements before Selecting them in JavaScript
8: Hiding the Overflow of an Element
10: Animating with a Game Loop
13: Dynamically Changing the SRC of an IMG Element
14: Passing Variables to Functions
15: Hiding and Showing Elements
16: Nesting If Statements and the Else If
17: Setting up an Intro Screen
19: Detecting Keyboard Input with Event Listeners
20: Moving an Element via Keyboard Input
21: Dynamically Adding Classes
22: Dynamically Creating HTML Elements
38: A String as an Array of Characters
39: Adding onclick Functionality with JavaScript