Free research, meanwhile, is exactly that - the ability to work on as many different technologies as you like, as long as you have the resources of research centres, power and money. Tech trees I experimented with included upgrading an infantry unit to a hacker and then master hacker (complete with jetpack!) for breaking into enemy security systems. I also did a little weapons research for my Ares fighter craft, giving me access to three kinds of sniper rifle and a sonic beam for cutting through enemy forces like French soft cheese.
The non-linear campaign lets you play as all four of the factions across Mars and 13 other worlds with wildly different environments, offering in excess of 150 hours gameplay. You certainly won't finish Earth 2160 over a lazy weekend.
Some of the missions revolve around gathering the game's three resources (water, metal, silicon - all available in various physical states including gas and liquid), but there are more gung-ho escapades such as escorting a dangerous prisoner on Titan and defending a research facility from a two-day onslaught on Io.
Drop-down menus help you negotiate the myriad of in-game options and you're always kept up to date with your goals on the mini-map, so you're never left confused about what to do next.
Interestingly, alongside the usual drag-and-drop control mechanisms, the game also offers a real-time mouse-aim feature similar to the recent Soldiers: Heroes of WWII. While not a vital part of the gameplay, this device is intended to provide a more dynamic, hands-on feel to the battles. Elsewhere, units can be set to automatically engage nearby hostiles so you don't have to baby-sit every element of your forces, but you can also pause the game and give specific orders to individuals or groups of units if you prefer.
Oh look, I'm getting too technical. Earth 2160's overriding wow-factor is the graphics - they're fantastic. The planets themselves have believable rock surfaces, shimmering pools of liquid, erupting geysers, moving skies and enough trees and fauna to give any botanist a chubby. As for the buildings and structures, they're incredibly detailed, organic affairs packed with steaming valves, moving panels, blinking lights, pumping pistons and fast-firing gun turrets. Not forgetting the army units, with shiny spaceships, mechs and vehicles constructed from dozens of colourful and strange metal alloys, and infantry dressed in different uniforms and loaded up with individually-modelled weaponry.
Dynamic lighting means that shadows move as the day/night cycle changes (see panel, Let There Be Light), and there's particle effects aplenty with realistic fog, dust that kicks up and weather effects such as acid rain and thunderstorms. Earth 2160 even has a fully-integrated physics system, demonstrated by a mission where you can fire lasers at large rocks to set off an avalanche of debris that rolls down the hill to crush an advancing army.
The camera can be rotated in full 3D, with a cracking zoom function that can view the action from way up high, then move down to within inches of the surface. More impressive still is the ability to take over any unit at any time, directly control it and see the world from a first-person perspective - each type of unit even has a unique HUD! In one memorable sequence, I jumped into a tank at ground level, just in time to watch a marauding squad of Terminator-style robots and hulking mechs stomp past like a scene straight out of Jurassic Park. Developers Zuxxez and Reality Pump have promised that even though 100 units on-screen is "not a problem", the actual total number of units possible is limited only by your PC's hardware.