Sadly it seems like this little trick only worked before the April 1st update/release. I tried it again and it didn't work anymore, sorry.

You can still try but you will most likely fail! :(

The first thing to do is to get inside the "Low Gravity Testing Facility".
To do this simply use the hole on the right to get behind the gate. Then destroy the rusty plates and you can finally get inside it.

Now enter the big "floating cube" (or whatever to call this).
To do so simply go on the stairs left and break the first window you'll find.

The last thing to do is simple: Jump on the fans till you float barely upwards/downwards, hold the right mouse button and now while doing so press W, A, S or D. You can also press 2 keys at once to get even more points!

VOILA! You can easily unlock the 2,000,000 milestone!

PS.: I was very lucky to get over 5,000,000 points for the screenshot :P