diff --git a/sketches/snake.js b/sketches/snake.js
index 188f28c..8f3c9ac 100644
--- a/sketches/snake.js
+++ b/sketches/snake.js
@@ -98,18 +98,28 @@ function buttonUpgradeAIPressed(){
 			break;
 
 		case "wallDetection":
+			AItype = "nearApple";
+			UpgradeAIPrice = 12;
+			break;
+
+		case "nearApple":
 			AItype = "appleBias";
-			UpgradeAIPrice = 15;
+			UpgradeAIPrice = 25;
 			break;
 
 		case "appleBias":
 			AItype = "snakeDetection";
-			UpgradeAIPrice = 35;
+			UpgradeAIPrice = 50;
 			break;
 
 		case "snakeDetection":
 			AItype = "smart";
-			UpgradeAIPrice = 100;
+			UpgradeAIPrice = 120;
+			break;
+
+		case "smart":
+			AItype = "survival";
+			UpgradeAIPrice = 300;
 			break;
 	}
 }
@@ -120,15 +130,15 @@ function buttonAddMoreApplesPressed(){
 	}
 	eatenApples -= AddMoreApplesPrice;
 	if (appleAmount < 5){
-		AddMoreApplesPrice = 1;
+		AddMoreApplesPrice += 1;
 	}else if (appleAmount < 10){
-		AddMoreApplesPrice = 2;
+		AddMoreApplesPrice += 2;
 	}else if (appleAmount < 20){
-		AddMoreApplesPrice = 3;
+		AddMoreApplesPrice += 3;
 	}else if (appleAmount < 50){
-		AddMoreApplesPrice = 4;
+		AddMoreApplesPrice += 4;
 	}else{
-		AddMoreApplesPrice = ceil(AddMoreApplesPrice*0.15);
+		AddMoreApplesPrice += ceil(AddMoreApplesPrice*0.15);
 	}
 	summonApple();
 	appleAmount++;
@@ -339,6 +349,10 @@ function snakeAI(){
 			snakeAIwallDetection();
 			break;
 
+		case "nearApple":
+			snakeAInearApple();
+			break;
+
 		case "appleBias":
 			snakeAIappleBias();
 			break;
@@ -350,9 +364,28 @@ function snakeAI(){
 		case "smart":
 			snakeAIsmart();
 			break;
+
+		case "survival":
+			snakeAIsurvival();
+			break;
 	}
 }
 
+function getAppleVisionDistance(){
+
+	if (appleAmount < 5){
+		return 2;
+	}else if (appleAmount < 15){
+		return 3;
+	}else if (appleAmount < 30){
+		return 5;
+	}else if (appleAmount < 60){
+		return 8;
+	}
+
+	return 12;
+}
+
 function directionToVector(direction){
 
 	switch(direction){
@@ -418,6 +451,36 @@ function getClosestApple(){
 	return bestApple;
 }
 
+function countFreeNeighbors(x, y){
+
+	let count = 0;
+
+	let dirs = [
+		[1,0],
+		[0,1],
+		[-1,0],
+		[0,-1]
+	];
+
+	for (let i = 0; i < dirs.length; i++) {
+
+		let nx = x + dirs[i][0];
+		let ny = y + dirs[i][1];
+
+		if (
+			nx >= 0 &&
+			ny >= 0 &&
+			nx < grid.length &&
+			ny < grid[0].length &&
+			grid[nx][ny] != 2
+		){
+			count++;
+		}
+	}
+
+	return count;
+}
+
 function snakeAIrandom() {
 	snakeDirection = floor(random(0, 4));
 }
@@ -439,6 +502,59 @@ function snakeAIwallDetection(){
 	}
 }
 
+function snakeAInearApple(){
+
+	let visionDistance = getAppleVisionDistance();
+
+	for (let i = 0; i < grid.length; i++) {
+		for (let j = 0; j < grid[0].length; j++) {
+
+			if (grid[i][j] != 1){
+				continue;
+			}
+
+			let distance =
+				abs(snake[0][0] - i) +
+				abs(snake[0][1] - j);
+
+			if (distance <= visionDistance){
+
+				let possibleDirections = [];
+
+				if (i > snake[0][0]){
+					possibleDirections.push(0);
+				}
+
+				if (j > snake[0][1]){
+					possibleDirections.push(1);
+				}
+
+				if (i < snake[0][0]){
+					possibleDirections.push(2);
+				}
+
+				if (j < snake[0][1]){
+					possibleDirections.push(3);
+				}
+
+				for (let k = 0; k < possibleDirections.length; k++) {
+
+					if (isDirectionSafe(possibleDirections[k])){
+
+						// 70% chance to follow apple
+						if (random() < 0.7){
+							snakeDirection = possibleDirections[k];
+							return;
+						}
+					}
+				}
+			}
+		}
+	}
+
+	snakeAIwallDetection();
+}
+
 function snakeAIappleBias(){
 
 	let apple = getClosestApple();
@@ -448,28 +564,37 @@ function snakeAIappleBias(){
 		return;
 	}
 
-	let possibleDirections = [];
+	let preferredDirections = [];
 
 	if (apple[0] > snake[0][0]){
-		possibleDirections.push(0);
+		preferredDirections.push(0);
 	}
 
 	if (apple[1] > snake[0][1]){
-		possibleDirections.push(1);
+		preferredDirections.push(1);
 	}
 
 	if (apple[0] < snake[0][0]){
-		possibleDirections.push(2);
+		preferredDirections.push(2);
 	}
 
 	if (apple[1] < snake[0][1]){
-		possibleDirections.push(3);
+		preferredDirections.push(3);
 	}
 
-	for (let i = 0; i < possibleDirections.length; i++) {
+	// 65% chance to go toward apple
+	if (
+		preferredDirections.length > 0 &&
+		random() < 0.65
+	){
 
-		if (isDirectionSafe(possibleDirections[i])){
-			snakeDirection = possibleDirections[i];
+		let direction =
+			preferredDirections[
+				floor(random(preferredDirections.length))
+			];
+
+		if (isDirectionSafe(direction)){
+			snakeDirection = direction;
 			return;
 		}
 	}
@@ -508,7 +633,7 @@ function snakeAIsmart(){
 	}
 
 	let bestDirection = snakeDirection;
-	let bestDistance = Infinity;
+	let bestScore = -999999;
 
 	for (let i = 0; i < 4; i++) {
 
@@ -525,9 +650,16 @@ function snakeAIsmart(){
 			abs(newX - apple[0]) +
 			abs(newY - apple[1]);
 
-		if (distance < bestDistance){
+		let freeNeighbors =
+			countFreeNeighbors(newX, newY);
 
-			bestDistance = distance;
+		let score =
+			(-distance * 3) +
+			(freeNeighbors * 8);
+
+		if (score > bestScore){
+
+			bestScore = score;
 			bestDirection = i;
 		}
 	}
@@ -535,6 +667,52 @@ function snakeAIsmart(){
 	snakeDirection = bestDirection;
 }
 
-function snakeAIrandomNowallHit(){
-	snakeDirection = floor(random(0, 4));
+function snakeAIsurvival(){
+
+	let bestDirection = snakeDirection;
+	let bestScore = -999999;
+
+	let apple = getClosestApple();
+
+	for (let i = 0; i < 4; i++) {
+
+		if (!isDirectionSafe(i)){
+			continue;
+		}
+
+		let vec = directionToVector(i);
+
+		let newX = snake[0][0] + vec[0];
+		let newY = snake[0][1] + vec[1];
+
+		let freeNeighbors =
+			countFreeNeighbors(newX, newY);
+
+		let score = freeNeighbors * 20;
+
+		if (apple != null){
+
+			let distance =
+				abs(newX - apple[0]) +
+				abs(newY - apple[1]);
+
+			score -= distance;
+		}
+
+		// avoid tunnels
+		if (freeNeighbors <= 1){
+			score -= 100;
+		}
+
+		// slight randomness
+		score += random(-3, 3);
+
+		if (score > bestScore){
+
+			bestScore = score;
+			bestDirection = i;
+		}
+	}
+
+	snakeDirection = bestDirection;
 }
\ No newline at end of file