2D grid-based game I wrote in high school
In high school, we were given an assignment to write a game in Java. I spent a lot of time creating tons of features that weren't necessary for the assignment. I created a 2D grid-based game where you are a hero traversing a dungeon full of monsters and treasure chests. This was my first large program, with a total of about ~3000 lines of code. I don't believe there would need to be anything extra needed to run the code.
Everything in the program was written by myself. This was my first experience with graphics and user interfaces, like buttons, listeners, windows, etc. All of the drawing used in the program were created by myself.