Spacecode

Spacecode teaches JavaScript by giving you a ship, a mission objective, and a small vocabulary of functions. forward(200), left(90), fire(), mine(), detonate(), delay(750). You write a program, you run it, and the spacecraft carries out the instructions.

I wrote the first version of this game in 2015. There is no separate editor pane and no mental translation between where you typed and what moved. Programs are short and their consequences are immediate and visible, which is the only version of a feedback loop a beginner will actually stay in.

Block-randomized studies#

Spacecode has been through several iterations over the past decade, each one shaped by a block-randomized study: players are assigned to variants, and the game records what they do at a much finer grain than whether they finished a level.

That data is unsentimental about design. A level you are proud of can turn out to be the point where players stop, and the cause is as often the wording of the mission as the difficulty of the puzzle. Blind spots surface the same way: where everybody hesitates is usually where the game assumed a concept it never taught.

It is a slightly unusual amount of rigor to apply to a game about space, and it is the reason the current version is better than the first one rather than just different.