You control a snake on a square grid. Each command moves it one or more steps in a direction. When the head reaches the food (*), the snake eats it and grows, and new food appears on a random empty cell. The game ends when the head hits a wall or the snake's own body. Nothing moves between your commands, so take your time.
Coordinates: rows are numbered from 1 at the top, columns from 1 at the left. up moves to row − 1, down to row + 1, left to column − 1 and right to column + 1.
Moving: up 3 takes 3 steps up. A multi-step move stops early when the snake eats food, so you can re-plan toward the next food. You can't reverse straight back into your neck (e.g. left while facing right). Moving into the cell your tail is leaving is allowed, unless the snake is still growing.
Text symbols: @ head, o body, * food, . empty, X crash site. The text board also lists how many steps you can go straight in each direction before crashing.
Options: small 12x12 boards score ×1.5 (less room); fast growth (+3 length per food instead of +1) scores ×1.5.
\nScore: food eaten × 10 × multiplier, plus an efficiency bonus of up to 20% of that: × 0.2 × min(1, shortest distances ÷ steps taken), measured over the food you ate (the distance is from the head to each food when it appeared). The game also ends if the snake fills the board.