there is some serious problem with the gravity and traction force in general physical constant of this simple platformer jumper... need also to fix ability for player to jump normally. output only functions to add or fix, without full original code.: const canvas=document.getElementById("game-canvas");const context=canvas.getContext("2d");canvas.width=640;canvas.height=480;const GRAVITY=20;const ENEMY_RADIUS=10;const PLAYER_RADIUS=10;const TRACTION=1;const OBSTACLE_COUNT=50;const OBSTACLE_GAP=0;let playerX=50;let playerY=250;let isPlayerAlive=true;let enemyX=400;let enemyY=500;let enemySpeedX=0;let enemySpeedY=0;let enemyMultiplier=0;let playerSpeedX=0;let playerSpeedY=0;let playerIsOnGround=false;let lasers=[];let shootingTimer=0;let obstacles=[];const obstacleWidth=100;const obstacleHeight=5;let offsetX=0;let offsetY=0;let scrollSpeed=1;function applyGravity(){if(!playerIsOnGround){playerSpeedY+=GRAVITY/60}}function applyTraction(){playerSpeedX*=TRACTION}function setPlayerStartPosition(){playerX=10;playerY=10}function respawnPlayer(){playerX=10;playerY=10;playerSpeedX=0;playerSpeedY=0;isPlayerAlive=true}function movePlayer(){if(!isPlayerAlive)return;playerX+=playerSpeedX;playerY+=playerSpeedY;if(playerX<0){playerX=0}if(playerX+PLAYER_RADIUS*2>canvas.width){playerX=canvas.width-PLAYER_RADIUS*2}if(playerY+PLAYER_RADIUS*2>canvas.height){respawnPlayer()}context.fillStyle="pink";context.fillRect(playerX-offsetX,playerY-offsetY,PLAYER_RADIUS*2,PLAYER_RADIUS*2)}function moveEnemy(){if(!isPlayerAlive)return;const targetIndex=findNearestObstacle(playerX,playerY);const targetX=obstacles[targetIndex].x+obstacleWidth/2;const targetY=obstacles[targetIndex].y+obstacleHeight/2;const epsilon=25;if(Math.abs(enemyX-targetX)>epsilon||Math.abs(enemyY-targetY)>epsilon){const angle=Math.atan2(targetY-enemyY,targetX-enemyX);enemySpeedX=Math.cos(angle)*2;enemySpeedY=Math.sin(angle)*2}else{enemySpeedX=0;enemySpeedY=0}enemyX+=enemySpeedX;enemyY+=enemySpeedY;context.fillStyle="cyan";context.fillRect(enemyX-ENEMY_RADIUS-offsetX,enemyY-ENEMY_RADIUS,ENEMY_RADIUS*2,ENEMY_RADIUS*2)}function findNearestObstacle(x,y){let minIndex=0;let minDistance=Number.MAX_VALUE;for(let i=0;i<obstacles.length;i++){const dx=x-(obstacles[i].x+obstacleWidth/2);const dy=y-(obstacles[i].y+obstacleHeight/2);const distance=Math.sqrt(dx*dx+dy*dy);if(distance<minDistance){minDistance=distance;minIndex=i}}return minIndex}function handlePlayerCollision(obstacle){const prevLeft=playerX-PLAYER_RADIUS*2;const prevRight=playerX;const prevTop=playerY-PLAYER_RADIUS*2;const prevBottom=playerY;const currLeft=playerX;const currRight=playerX+PLAYER_RADIUS*2;const currTop=playerY;const currBottom=playerY+PLAYER_RADIUS*2;const obstacleLeft=obstacle.x;const obstacleRight=obstacle.x+obstacle.width;const obstacleTop=obstacle.y;const obstacleBottom=obstacle.y+obstacle.height;if(prevBottom<=obstacleTop&&currBottom>obstacleTop){playerY=obstacleTop-PLAYER_RADIUS*2;playerSpeedY=0;return true}else if(prevTop>=obstacleBottom&&currTop<obstacleBottom){playerY=obstacleBottom;playerSpeedY=0;playerIsOnGround=true;return true}else if(prevLeft>=obstacleRight&&currLeft<obstacleRight){playerX=obstacleRight;playerSpeedX=0;return true}else if(prevRight<=obstacleLeft&&currRight>obstacleLeft){playerX=obstacleLeft-PLAYER_RADIUS*2;playerSpeedX=0;return true}return false}function isColliding(x,y,width,height){for(const obstacle of obstacles){if(obstacle&&x<obstacle.x+obstacle.width&&x+width>obstacle.x&&y<obstacle.y+obstacle.height&&y+height>obstacle.y){return obstacle}}return null}function checkCollision(){detectObstacleCollision()}function detectObstacleCollision(){const obstacle=isColliding(playerX,playerY,PLAYER_RADIUS*2,PLAYER_RADIUS*2);if(obstacle){handlePlayerCollision(obstacle)}else{playerIsOnGround=false}}function shootLaser(){const laserSpeed=2;const angle=Math.atan2(playerX-enemyX);const laserSpeedX=Math.cos(angle)*laserSpeed;const laserSpeedY=Math.sin(angle)*laserSpeed;lasers.push({x:enemyX+ENEMY_RADIUS,y:enemyY+ENEMY_RADIUS,speedX:laserSpeedX,speedY:laserSpeedY})}function moveLasers(){let playerHit=false;for(let i=0;i<lasers.length;i++){const laser=lasers[i];laser.x+=laser.speedX;laser.y+=laser.speedY;if(!playerHit&&laser.x>=playerX&&laser.x<=playerX+PLAYER_RADIUS*2&&laser.y>=playerY&&laser.y<=playerY+PLAYER_RADIUS*2){const randomColor="rgb("+Math.floor(Math.random()*256)+","+Math.floor(Math.random()*256)+","+Math.floor(Math.random()*256)+")";context.strokeStyle=randomColor;context.beginPath();context.moveTo(laser.x,laser.y);context.lineTo(laser.x+laser.speedX,laser.y+laser.speedY);context.lineWidth=3;context.stroke();playerHit=true;isPlayerAlive=false}if(isOutOfBounds(laser.x,laser.y,0,0)){lasers.splice(i,1);i}}if(playerHit){playerX=-100;playerY=-100}}function drawLasers(){context.fillStyle="red";for(const laser of lasers){context.beginPath();context.arc(laser.x,laser.y,5,0,Math.PI*2);context.fill()}}function drawObstacles(){context.fillStyle="yellow";for(const obstacle of obstacles){context.fillRect(obstacle.x,obstacle.y,obstacle.width,obstacle.height)}if(obstacles.length&&isOutOfBounds(obstacles[0].x,obstacles[0].y,obstacleWidth,obstacleHeight)){generateNewObstacle("up")}if(obstacles.length&&isOutOfBounds(obstacles[obstacles.length-1].x,obstacles[obstacles.length-1].y,obstacleWidth,obstacleHeight)){generateNewObstacle("down")}}function createObstacles(){for(let i=0;i<OBSTACLE_COUNT;i++){const obstacleX=Math.random()*(canvas.width-obstacleWidth);const obstacleY=i*(canvas.height/OBSTACLE_COUNT)+OBSTACLE_GAP;obstacles.push({x:obstacleX,y:obstacleY,width:obstacleWidth,height:obstacleHeight})}}function setPlayerStartPosition(){const startingObstacle=obstacles[0];playerX=startingObstacle.x+obstacleWidth/2-PLAYER_RADIUS;playerY=startingObstacle.y-PLAYER_RADIUS*2}function isOutOfBounds(x,y,width,height){return x<0||x>canvas.width||y<0||y>canvas.height}function generateNewObstacle(playerDirection){if(playerDirection==="up"){obstacles.shift();const obstacleX=Math.random()*(canvas.width-obstacleWidth);const obstacleY=obstacles.length>0?obstacles[obstacles.length-1].y-canvas.height/OBSTACLE_COUNT-OBSTACLE_GAP:canvas.height;obstacles.push({x:obstacleX,y:obstacleY,width:obstacleWidth,height:obstacleHeight})}else if(playerDirection==="down"){obstacles.pop();const obstacleX=Math.random()*(canvas.width-obstacleWidth);const obstacleY=obstacles.length>0?obstacles[0].y+canvas.height/OBSTACLE_COUNT+OBSTACLE_GAP:0;obstacles.unshift({x:obstacleX,y:obstacleY,width:obstacleWidth,height:obstacleHeight})}}function checkEnemyDeath(){if(isPlayerAlive&&playerSpeedX>=0&&playerY+PLAYER_RADIUS*2>enemyY-ENEMY_RADIUS&&playerX+PLAYER_RADIUS*2>enemyX-ENEMY_RADIUS&&playerX<enemyX+ENEMY_RADIUS){playerIsOnGround=false;playerSpeedY=-20;setTimeout(()=>{playerSpeedY=0},100);enemyX=-100;setTimeout(spawnNewEnemy,1e3);enemyMultiplier++}}function spawnNewEnemy(){enemyX=Math.random()*(canvas.width-ENEMY_RADIUS*2);enemyY=Math.random()*(canvas.height-ENEMY_RADIUS*2);for(let i=0;i<enemyMultiplier-10;i++){shootLaser()}}function draw(timestamp){context.fillStyle="black";context.fillRect(0,0,canvas.width,canvas.height);const elapsedSeconds=(timestamp-lastFrameTime)/1e3;lastFrameTime=timestamp;applyGravity(elapsedSeconds);applyTraction();movePlayer();moveEnemy();moveLasers();detectObstacleCollision();drawLasers();drawObstacles();checkEnemyDeath();if(playerY<offsetY+PLAYER_RADIUS*2&&playerX>offsetX-PLAYER_RADIUS*2&&playerX<offsetX+obstacleWidth+PLAYER_RADIUS*2){offsetY-=canvas.height/OBSTACLE_COUNT;playerY+=canvas.height/OBSTACLE_COUNT;enemyY+=canvas.height/OBSTACLE_COUNT;generateNewObstacle()}requestAnimationFrame(draw)}let lastFrameTime=0;createObstacles();setPlayerStartPosition();draw();document.addEventListener("keydown",event=>{if(event.code==="KeyA"){playerSpeedX=-5}if(event.code==="KeyD"){playerSpeedX=5}if(event.code==="KeyW"&&(playerIsOnGround||playerY<=offsetY+PLAYER_RADIUS*2)){playerSpeedY=-20;playerIsOnGround=false}});document.addEventListener("keyup",event=>{if(event.code==="KeyA"||event.code==="KeyD"){playerSpeedX=0}});