Primordia is a point-and-click adventure game set in the distant future, in a world in which no humans remain and the Earth is inhabited only by robots. You play as Horatio Nullbuilt and his assistant/son Crispin Horatiobuilt.
Horatio has lost his memory, and has spent the time since then trying to rebuild the crashed airship on which he finds himself. The game begins with the ship's power core being stolen, which leads Horatio to explore further than he previously has in search of a new power source and eventually to Metropol, apparently the last remaining city on Earth.
Although there's nothing particularly innovative or special about the plot, it manages to remain engaging enough for the most part, and the voice acting is great. The actual gameplay is pretty good as well, being surprisingly free of adventure game logic. Most solutions make sense and there are even multiple solutions to several problems. Also noteworthy is the fact that Horatio won't steal things. Most adventure game characters will (and must) pick up anything that's not nailed down, but Horatio actually respects others' property and will only take things that are clearly unwanted and actually serve some conceivable purpose.
There are only really three problems with this game. Firstly, although the multiple solutions are great, you can quite easily lock yourself out of some of the content without even realising it. There are no unwinnable states or anything like that, just a few bits of backstory, extra dialogue, etc. that you can miss out on. Fortunately, if you want to play through it again to get the stuff you missed then it's really easy to do so. Once you know the solutions you won't have to sit through lengthy cutscenes or repeated animations to get to the bits you want to see again.
Secondly, sometimes you can travel in directions that aren't obvious. I spent ages wandering back and forth trying to find where I needed to go next because I didn't realise that the undercity extended off to the right.
Thirdly, there is a little bit of pixel-hunting. It's not terrible and once you've spotted the hotspot it's very easy to click, there's nowhere where you have to click a specific pixel or anything, it's just that a few things are really hard to spot unless you know to look for them.
Those are really pretty minor issues though and this is definitely an example of what adventure games should be like. With shit like Sam & Max: The Devil's Playhouse and Gemini Rue receiving such great praise it's really a shame that games like this one or Hector: Badge of Carnage seem to slip by mostly under the radar.
As a quick summary, I'd say that if you've played Beneath a Steel Sky then you'll find a lot of similarities, and if you enjoy actually good adventure games like the Blackwell series then you should definitely play this one.