I agree I also forgot how many great Australian produced games are out there. SSG (Strategic Simulation Games) with reach for the stars widely regarded as putting  4X games on the map, who also made Gold of the Americas, the Warlord games and Fallout Tactics: Brotherhood of Steel to name a few,then there is Pandemic with games like Star Wars Battlefront 1 and II - The Saboteur - Mercenaries 1 and 2 - Dark Reign - Full Spectrum Warrior -Destroy all humans. and I almost forgot my essential collection series copy of Battlezone II combat commander. 

Lets not forget Melbourne House/ Beam Software/ Khrome etc that gave to me my favourite Dreamcast racing game LeMan 24 hours - Shadowrun snes - The Hobbit and way of the exploding fist to name a few.

Medieval Total War II was iirc made in Queensland, it came to mind because I remember the editor of Hyper Australia's biggest selling multiformat game magazine left to go work on it for Creative assembly Australia. 

That's just a few Australian developers adding all those other games mentioned by our fellow VGCharters in the thread, and the many more that are invariably missed in endeavours like this increases our realisation of how many great games came out of here, so I will end by mentioning one of my favorite Australian produced games and that is irrational games Freedom Force.