Titan armor doesn't remind me of Halo at all - only played the first one, so you may be speaking of something else. The lines and the palette chosen remind me of classic sci-fi art. The warlock helmet seems to share the contours of the EVA helmet, but that could be said of a lot of helmets. But hey, that's how I feel. We all compare new things to other things in our own experience and put them in categories that fit for us.