I think they are more like brother and sister.
^ You hit the nail right on the head. I think they'll leave it ambiguous for good so fans keep guessing (and buying/playing)I see it being both ways. They could be together on a more personal level away from work or they could just be really good friends. Some of the events they've been through together, especially some of the endings for the original Resident Evil, allude to a relationship but are ambiguous enough that they could be construed as "just friends."
I honestly think that Capcom is keeping the true nature of their relationship a secret on purpose just to keep players in suspense and playing to find out what happens. Either that or they creators/writers are indecisive and change too often to really set up a stable view of the relationship.
Much like comic books. The writers change so often, and each writer has their own opinions and feelings about each character and situation that it's almost impossible to create a long-lasting relationship because everyone feels so differently. Even if one person sets up something in one book/issue - or in this case, game - unless they're writing the character for a long period of time, another writer will immediately come in and retcon what they last author did to suit their own means.
To be honest, we'll probably never know for sure.
The original RE1 was my first RE game (although it was RE3 that originally caught my attention), and when I saw Chris and Jill, I expected them to be a couple, either right from the start or by the end of the game. Isn't it always like that? Almost every TV show, movie or game starring a male and a female lead ends up shipping them sooner or later. And those two were roughly the same age, they looked alright together, so I thought, why not? But when I played the game, I realised they didn't really spend much time together, and the little interaction they had didn't seem romantic to me. It became even less "romantic" in later games, so I agree with the brother/sister thing.
People in favour of Valenfield keep bringing up the reunion scene in RE5 where Chris cradles Jill in his arms, but that doesn't mean anything to me either because Jill was weak at the time and had just gone through hell, and it's Chris we're talking about, he just loves touching people and does it all the time. In the Remake, he gets close to Rebecca and grabs her shoulders every time he sees her (it gets ridiculous after a while), and also holds Richard's hand and strokes his cheek as if they were lovers, yet I never see anyone shipping Chris with either of them. It's clear that Jill means a lot to him and vice versa, and I can see why given how much they've been through, but a romance? Not so much.
I think the closest thing we have to an "official" couple in this series is LeonXAda, who kissed at the end of RE2's canon scenario. Sure, a kiss doesn't mean they're in a relationship, it also doesn't mean they're going to be together forever and marry and have children, but it does mean there's some kind of attraction, and I don't see that between Chris and Jill. But I guess the relationships in RE are like the stories of the Bible; you can read into them whatever you want and even find "proof" for your assumption if you just look hard enough.
Chris's one true love is football.
Full disclosure: I love this playthrough.
I love them. Especially Jake.
I think they are friend zoned and more or less have a sibling like relationship. Plus I don't think Chris has any interest in sexual relationships or girls in general. He never flirts or has any display of interests in the opposite sex, where as Leon, Claire, and a fair few others make comments and compliments on those who they have an interest in. Chris is very focused on his belief and dedication to fighting bio-terrorism. His whole existence is shaken to that core belief and I don't see him settling down for anything except justice. He has said time and time again that he is willing and will die for this cause and belief. He will fight until the end and WILL NOT live in a world where terror exists. Read on how many missions he's partaken and you'll see that he's had no time to just "hook up".
Chris is either "The 40 year old virgin" or he had his fun in high school. XD I thought it was established by the majority of RE fans that Chris has zero interests in sexual endeavors. I swear to god that he was born without that nature of his brain dysfunctional.
I think him and Piers had something going on... :suggestive: