Rare's cancelled Perfect Dark game would have been built around an "open-ended sandbox" that felt similar to Deus Ex, an ex-Rare developer has revealed.

Speaking to Eurogamer, Chris Seavor, who left Rare in January 2011 and now heads up indie developer Gory Detail, said that Perfect Dark Core had been in production "for nearly a year" before Microsoft pulled the plug, and that the game would have put a darker twist on Rare's shooter series.

"We did Perfect Dark Core, which was going okay," he said. "It was all right. There was a load of tech. I was trying to do something quite different with that.

"I wanted to get away from the go around the corner, shoot, on rails kind of game, which a lot of games are doing now. If you look back at what games were like, like GoldenEye and Perfect Dark, all the old games like Deus Ex, you compare how complex they were in terms of the multiple paths, first-person shooters now have gone backwards in time in terms of design, but way ahead in terms of graphics. It's a bit of a shame. But I was trying to get it back to that more open-ended sandbox feel to first-person shooters."

Seavor added that the game would have felt like first-person action-RPG Deus Ex, and wouldn't have been "as narrow as something like Call Duty, where it's like, walk, cutscene, walk, cutscene.

"It was definitely going to be, you could go over here and do this over here, or you could go over here and do this over here," he continued. "And then it would bottleneck down to something that would then take you to the next bit. It was very much about missions and storyline."

He continued: "[Deus Ex is] one of my favourite games. I really like that game. I thought, if you could get something like that but make it look amazing, you're probably on a fairly good direction to having a hit."

There would have been a Mirror's Edge feel to the game, too, Seavor suggests, saying that "it had some nice mechanics. We were doing all the parkour jumping from walls stuff."