To @Sykin's answer, I would add:

#Bug If you press down and then left faster than the snake takes to slither "one step", the snake turns around and slithers over itself.

#Indentation, code style, and code consistency I find that JSLint really helps me get a consistent code style.

#Strict mode I suggest you use strict mode in your JS, by starting with a line "use strict";

To @Sykin's answer, I would add:

Bug

If you press down and then left faster than the snake takes to slither "one step", the snake turns around and slithers over itself.

Indentation, code style, and code consistency

I find that JSLint really helps me get a consistent code style.

Strict mode

I suggest you use strict mode in your JS, by starting with a line "use strict";

To @Sykin's answer, I would add:

#Bug If you press down and then left faster than the snake takes to slither "one step", the snake turns around and slithers over itself.

#Indentation, code style, and code consistency I find that JSLint really helps me get a consistent code style.

#Strict mode I suggest you use strict mode in your JS, by starting with a line "use strict";

To @Sykin's answer, I would add:

#Bug If you press down and then left faster than the snake takes to slither "one step", the snake turns around and slithers over itself.

#Indentation, code style, and code consistency I find that JSLint really helps me get a consistent code style.

#Strict mode I suggest you use strict mode in your JS, by starting with a line "use strict";

To @Sykin's answer, I would add:

#Bug If you press down and then left faster than the snake takes to slither "one step", the snake turns around and slithers over itself.

#Indentation and code style I find that JSLint really helps me get a consistent code style.

#Strict mode I suggest you use strict mode in your JS, by starting with a line "use strict";

To @Sykin's answer, I would add:

#Bug If you press down and then left faster than the snake takes to slither "one step", the snake turns around and slithers over itself.

#Indentation, code style, and code consistency I find that JSLint really helps me get a consistent code style.

#Strict mode I suggest you use strict mode in your JS, by starting with a line "use strict";