I DID IT!!!!!
But actually that was a lucky one. Bogey Beta got stuck behind an obstacle and was unable to move out for most of the time, allowing me to kill Bogey Alpha quickly.
Just when I wore Beta's HP down to half with the Assault Rifle it suddenly freed itself, but with it the only enemy left I didn't find it too hard to use my HMG to keep fighting. Finished it with a boost kick + a few more rounds!
Luck was finally with me, though strictly speaking I didn't really complete the challenge very legitimately.
All my played games are exactly 1000G.
10000G for 10 games on 7/12/2010
20000G for 20 games on 9/8/2011
30000G for 30 games on 6/5/2012
40000G for 40 games on 24/9/2012
50000G for 50 games on 19/5/2013
60000G for 60 games on 12/1/2014
Last edited by ImaginaryRuins; 08-24-2013 at 07:19 AM.