Here is a small guide by Cristal on how to get the Aion RU 4.0 client and log in to test out 4.0! Credits: Cristal

https://ru.4game.com/aion/play/

login with facebook

on the bottom there is a launcher ~4mb, install it

then you need a bookmark with this as url



Code:
javascript:(function(){                if(typeof require === 'undefined'){alert('launch on 4game.com.');return;}                var _breq = require.config({baseUrl: '/js/bookmarklets'});                _breq(['game_env'], function(b) {b.start();});            })()


on aion website click on that bookmark and you should see a small window on the left with QA, PTS, PTS2, PTS3, LIVE
chose any pts

and then click yellow button to start downloading



You now know how to download the client.

Not sure if login is straight forward or not, but I'll update the guide if it isn't.

PS: Make sure it says Aion [PTS] on the 4game page, or else you'll probably download the live version. >.< I made that mistake but was only like few minutes in.