Read creating a platform game in as3 if you haven’t already.

import flash.display.*;
import flash.events.*;
stage.frameRate = 30;
stage.addEventListener(Event.ENTER_FRAME, run);
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed);
stage.addEventListener(KeyboardEvent.KEY_UP, keyReleased);

var gravity:Number = 0.2;
var velocity:Number = 0;
var lspeed:int = -2;
var rspeed:int = 2;
var goleft:Boolean = false;
var goright:Boolean=false;
var attemptJump:Boolean=false;
var char:MovieClip = new MovieClip();
char.graphics.lineStyle(2, 0×112233);
char.graphics.beginFill(0×112233);
char.graphics.drawRect(200, 0, 20, 50);
char.graphics.endFill();
addChild(char);

var land:MovieClip = new MovieClip();
land.graphics.lineStyle(2, 0×112233);
land.graphics.beginFill(0×112233);
land.graphics.drawRect(0, 350, 400, 25);
land.graphics.endFill();
addChild(land);

function keyPressed(event:KeyboardEvent):void {
switch (event.keyCode) {
case Keyboard.UP :
attemptJump = true;
break;
case Keyboard.LEFT :
goleft = true;
break;
case Keyboard.RIGHT :
goright = true;
break;
}
}
function keyReleased(event:KeyboardEvent):void {
switch (event.keyCode) {
case Keyboard.UP :
attemptJump = false;
break;
case Keyboard.LEFT :
goleft = false;
break;
case Keyboard.RIGHT :
goright = false;
break;
}
}

function run(event:Event) {
char.y+=velocity;
velocity+=gravity;
if (char.hitTestObject(land)) {
velocity = 0;
}
if (attemptJump==true) {
velocity =-5;
}
if (goleft==true) {
char.x+=lspeed;
}
if (goright==true) {
char.x+=rspeed;
}
}

I’ve always wanted to create a platform game, so here goes.