Two weeks ago, I released my classic browser-based snake game—a project I started 15 years ago—under a free and open-source license.

In this post, I’ll walk you through the game’s fundamental loop and explain the various systems that bring it to life.

The basics

The game unfolds on a board that measures at least 30 × 20 squares.

On the game board, a snake is moving.

Movement

At the start of each game, players can set the initial speed of the snake.

Once the game begins, you control the snake’s direction in real time. Although the snake will crash into its own tail, it can pass through the board’s boundaries freely. This design choice not only expands the range of movement options but also deepens the strategic complexity of navigation.

Food

A single gray food item occupies one square on the board at all times. Consuming this food momentarily boosts the snake’s speed, permanently extends its body, and earns points.

In addition, colorful food items appear at random on unoccupied squares. After a delay—proportional to the distance between the snake and the food—these items either change to a more common color or vanish. Eating these colorful pieces results in a significant speed boost and is equivalent to consuming several gray items at once.

Dynamic difficulty

The game adjusts its difficulty based on your performance:

• Missed opportunities: If you consistently fail to eat colorful food, they will spawn more frequently, albeit with a lower probability of being rare.

• Rewarding precision: Successfully consuming every colorful food increases the likelihood of rarer, high-value items appearing as a reward for your skillful play.

Achievements

The game’s narrator acknowledges your milestones with floating text that celebrates in-game achievements. There are two achievement tracks:

• Score-based achievements: Points are segmented into distinct ranges, each associated with its own color and set of milestone messages, tracking your progress.

• Event-based achievements: These recognize rare occurrences—whether it’s a streak of consecutive food items consumed without changing direction, narrowly avoiding the snake’s tail, or consuming colorful food just before it disappears.