Duke Nukem is made out pixels.
Isaac Clarke ain't.
Duke Nukem went through hell.
Isaac Clarke went through hell, fixed it, got home, got put in a psychological ward, went through hell AGAIN escaping that ward, and then went through hell all over again, and then killed all the things from hell.
And the story's a helluva lot better than Duke Nukem. That's just shoot-everything. This is a bit more than that. You know, kinesis, stasis, zero-g, space, hell three or four times over, interesting, original gun concepts, actual dialogue, graphics, etc.
And has Mass Effect armor.