You need a fast computer and a fast browser. I got significantly better response on an Alienware than on a Vaio business oriented machine.
Go to this page and select your Android screen size and orientation - https://www.manymo.com/emulators
It's the real deal - Android runs in your browser as an emulated OS. You get five minutes play without creating an account. You can create an account and get 10 free logins per month. Anything more and you have to pay.
There's a command line tool if you want to get serious which gives you some developer options and more speed.