[PC] Steam - Guardians of Orion (77% Positive on Steam) (90% off) - $0.99 US (~$1.60 AUD) - Steam

Also note that Orcs must die! is also still $0.99 US: http://store.steampowered.com/app/102600/
If you do not have that game yet, get it at that price. Very enjoyable.

Edit: user nofighting has pointed out that their first game called Orion Prelude is also 51% off and costs 0.49 US (~0.80 AUD) until 4 March: http://store.steampowered.com/app/104900/
Orion Prelude is owned by 2 million people, in last 2 weeks 46,051 played the game (source: SteamSpy)

He/she has also pointed out that:

if you purchase and login to Guardians of Orion before 1 May 2016 you receive Founder status
source :
http://steamcommunity.com/games/104900/announcements/detail/…
OR
http://steamcommunity.com/games/104900/announcements/detail/… (more detailed)

Thank you nofighting.

Guardians of Orion (owned by more than 41,000 people and played in the last 2 weeks by 9,265 people (source: SteamSpy) - keep in mind this has only been out for two months.

From the Steam page:

"Guardians of Orion (GOO) is a Hyper-Adrenaline, Sci-Fi Shooter featuring Dinosaurs and Robots focused on Accessibility, Over-The-Top Gameplay, Power-Ups, 4-Player Survival Co-op Multiplayer, Destruction, Gibs, Gore and more! 'Guardians of Orion' is the Spiritual Successor and Prequel to the multi-platinum indie hit: 'ORION: Prelude'.

[ Key Features ]

Survival Co-Op Gameplay
10+ Weapons & Gear
10 Dinosaurs/Creatures
7 Dinosaurs
5 Power Ups
Loot + Inventory
Gear + Crafting
4 Multiplayer Maps
3 Robot Drones
5 Guardian Classes
Destruction
Gibs & Gore
Fatalities
Full Gamepad Support
Achievements
Progression/RPG Systems
Lobbies & Browsers"