reduce the lerp fluctuation of entities a bit. you probably can make these entities to come from the right side and try to jump on platforms in derection to left. I'm not sure which simple logic you can add for this, but don't use any libraries or frameworks for neural network agents. also, try to add some main ground platform at the bottom that will expand in dependence of canvas shifting or else, you understand. :class Platform {
constructor(x, y, w, h) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
}
collidesWith(obj) {
if (obj.y + obj.h <= this.y) return false;
if (obj.y >= this.y + this.h) return false;
if (obj.x + obj.w <= this.x) return false;
if (obj.x >= this.x + this.w) return false;
const objAbove = obj.y + obj.h - obj.vy <= this.y;
const objBelow = obj.y - obj.vy >= this.y + this.h;
const objLeft = obj.x + obj.w - obj.vx <= this.x;
const objRight = obj.x - obj.vx >= this.x + this.w;
if (obj.vy > 0 && objAbove && !objBelow) {
obj.y = this.y - obj.h;
obj.vy = 0;
obj.jumping = false;
return true;
}
if (obj.vy < 0 && !objAbove && objBelow) {
obj.y = this.y + this.h;
obj.vy = 0;
return true;
}
if (obj.vx < 0 && objRight) {
obj.x = this.x + this.w;
obj.vx = 0;
return true;
}
if (obj.vx > 0 && objLeft) {
obj.x = this.x - obj.w;
obj.vx = 0;
return true;
}
return false;
}
}

class Player {
constructor(x, y, w, h) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
this.vx = 0;
this.vy = 0;
this.jumping = false;
}
move(keys) {
const friction = .8;
const gty = 0.8;
if (keys[87] && !this.jumping) {
this.vy -= 10;
this.jumping = true;
}
if (keys[68]) {
this.vx += 0.8;
}
if (keys[65]) {
this.vx -= 0.8;
}
this.vx *= friction;
this.vy += gty;
this.x += this.vx;
this.y += this.vy;
if (this.x < 0) {
this.x = 0;
}
if (this.y < 0) {
this.y = 0;
}
if (this.x + this.w > canvas.width) {
this.x = canvas.width - this.w;
this.vx = 0;
}
if (this.y + this.h > canvas.height) {
this.y = canvas.height - this.h;
this.vy = 0;
this.jumping = false;
}
}
}

class Projectile {
constructor(x, y, vx, vy) {
this.x = x;
this.y = y;
this.vx = vx;
this.vy = vy;
this.radius = 3;
this.color = "red";
}
update() {
this.x += this.vx;
this.y += this.vy;
}
draw(ctx) {
ctx.beginPath();
ctx.arc(this.x, this.y, this.radius, 0, 2 * Math.PI);
ctx.fillStyle = this.color;
ctx.fill();
}
}



class Entity {
constructor() {
this.x = canvas.width;
this.y = Math.random() * canvas.height;
this.w = 10;
this.h = 10;  

this.vy = 0;
this.jumping = false;
this.projectiles = [];
this.color = "blue";


}
jump() {
if (!this.jumping) {
this.vy -= 25 - Math.random() * 25;
this.jumping = true;
}
}
update(platforms) {
for (let i = 0; i < platforms.length; i++) {
platforms[i].collidesWith(this);
}
const friction = .99;
const gty = 1;
this.vx = friction;
this.vy += gty;
this.x += this.vx;
this.y += this.vy;this.period = Math.PI;
this.minVx = -2 + Math.sin(Math.random() * 2 * Math.PI) * 2;
this.maxVx = -10 + Math.cos(Math.random() * 2 * Math.PI) * -20;
  this.vx = this.vxForce = randomRange(this.minVx, this.maxVx);
    const t = performance.now() / 1000;
    const wave = Math.sin(t * Math.PI / this.period);
    this.vxForce = lerp(this.maxVx, this.minVx, (wave + 8) / 432);
    this.x += this.vxForce;      
if (Math.random() < .01) {
this.projectiles.push(new Projectile(this.x, this.y, -2 - Math.random() * 6, -2 + Math.random() * 8));
}
for (let i = 0; i < this.projectiles.length; i++) {
this.projectiles[i].update();
if (this.projectiles[i].x < 0 || this.projectiles[i].y < 0 || this.projectiles[i].x > canvas.width || this.projectiles[i].y > canvas.height) {
this.projectiles.splice(i, 1);
i;
}
}
if (Math.random() < .01) {
this.jump();
}
}
draw(ctx) {
ctx.fillStyle = this.color;
ctx.fillRect(this.x, this.y, this.w, this.h);
for (let i = 0; i < this.projectiles.length; i++) {
this.projectiles[i].draw(ctx);
}
}
}

function randomRange(min, max) {
return Math.random() * (max - min) + min;
}

function lerp(a, b, t) {
return a * (1 - t) + b * t;
}

class Game {
constructor(canvas) {
this.canvas = canvas;
this.ctx = canvas.getContext("2d");
this.platforms = [];
this.player = new Player(10, 10, 10, 10);
this.scrollSpeed = 0.5;
this.entities = [];
this.entitySpawnRate = .1;
this.entitySpawnTimer = 1;
this.entityIncreaseFactor = .1;
this.keys = {};
this.platforms.push(new Platform(0, canvas.height - 10, canvas.width, + 1));
  for (let i = 0; i < 10; i++) {
this.createRandomPlatform();
}
document.addEventListener("keydown", evt => {
this.keys[evt.keyCode] = true;
});
document.addEventListener("keyup", evt => {
delete this.keys[evt.keyCode];
});
requestAnimationFrame(this.update.bind(this));
}
createRandomPlatform() {
const x = this.canvas.width;
const y = Math.random() * this.canvas.height;
const w = 20 + Math.random() * 50;
const h = 5;
this.platforms.push(new Platform(x, y, w, h));
}
update() {
this.player.move(this.keys);
for (let i = 0; i < this.platforms.length; i++) {
this.platforms[i].collidesWith(this.player);
this.platforms[i].x -= this.scrollSpeed;
}
for (let i = 0; i < this.entities.length; i++) {
if (this.entities[i]) {
this.entities[i].update(this.platforms);
if (this.entities[i].x < 0) {
this.entities.splice(i, 1);
i;
for (let j = 0; j < this.entityIncreaseFactor; j++) {
this.entities.push(new Entity());
}
} else {
for (let j = 0; j < this.entities[i].projectiles.length; j++) {
if (this.entities[i].projectiles[j].x > this.player.x && this.entities[i].projectiles[j].x < this.player.x + this.player.w && this.entities[i].projectiles[j].y > this.player.y && this.entities[i].projectiles[j].y < this.player.y + this.player.h) {
this.player.vy -= 20;
this.player.jumping = true;
this.entities[i].projectiles.splice(j, 1);
j;
}
}
this.entities[i].draw(this.ctx);
}
}
}
this.player.x -= this.scrollSpeed;
if (this.platforms[this.platforms.length - 1].x < this.canvas.width - 20) {
this.createRandomPlatform();
}
this.entitySpawnTimer++;
if (this.entitySpawnTimer >= 60 / this.entitySpawnRate) {
this.entitySpawnTimer = 0;
this.entities.push(new Entity());
this.entitySpawnRate += .001;
this.entityIncreaseFactor = Math.min(this.entityIncreaseFactor + .001, .001);
}
this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
for (let i = 0; i < this.platforms.length; i++) {
let p = this.platforms[i];
this.ctx.fillRect(p.x, p.y, p.w, p.h);
}
for (let i = 0; i < this.entities.length; i++) {
this.entities[i].draw(this.ctx);
}
this.ctx.fillRect(this.player.x, this.player.y, this.player.w, this.player.h);
requestAnimationFrame(this.update.bind(this));
}
}

let canvas = document.createElement("canvas");
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
document.body.appendChild(canvas);
new Game(canvas);