The editor supports rainbow parenthesis and provides a matching highlight behind the form your cursor is inside of. It also uses Parinfer, a beginner-friendly Lisp editing mode. For any file, you can optionally enable an instaREPL, which will show the live evaluations of your code to the left. Reader errors are displayed inline, so you see them immediately.
Hold down the control key (or command on OS X), and you'll see shortcut hints appear over every applicable widget. Holding it while pressing Up/Down/Enter will move your selection in the project tree and expand/collapse directories. Holding it while pressing PgUp/PgDn will move between recent files, much like tabs in other IDEs but without the UI clutter.