^Continuing here instead,
I don't have any trouble with immersion, but I wouldn't define it this way. For the first time ever immersive isn't being underlined by the spellchecker. So it's officially a word now I guess, or Firefox has switched to a more freewheeling dictionary.
Immersion is unique to games. Immersive would've been a word decades ago if it had anything to do with books or movies. People confuse it, saying immersive when they mean engrossing. You can be engrossed in a book, or a film, but never immersed in it. To be immersed is to be dipped into it.
To be engrossed is to have your full attention. To be immersed is closer to hypnotism or dreaming, your brain is essentially convinced that it is in a new reality completely.
So what can be immersive? Can graphics be immersive? Not really. As long as graphics are not glitch-y they are sufficiently immersive. Can language be immersive? Not really. As long as language is consistent it is immersive. The same goes for all of the senses and uses for them.
For example, cartoons cannot be immersive. They can come in any visual style, and we accept them, just as we accept the visual style of our particular reality. If you dream you are in a cartoon, it feels real, and if it feels real then you are immersed. We don't say dreams are immersive because we don't make dreams as such, but dreams and our reality are the only real analogue to video games we have. This is why guys like David Cronenberg obsess over video games even when they don't know or understand the first thing about them, but they understand their relationship to reality/realities.
In practical terms, what then enhances immersion? Well I think we are incredibly biased to first-person video games where immersion is paramount. This is just because we spend so much time in a first-person reality. If somehow we were freed from that our attitudes/bias might change radically; but I don't think playing lots of non-first-person games could ever achieve that even in the slightest.
The senses have to be excited from all directions. Again this is just a biological bias. We are used to that. In real terms this means everything that can produce a sound should produce a sound. Again it doesn't have to be a realistic sound, but this seems like another strange bias, because there are very few examples of non-realistic sounds in our history of music and recording. Cartoon sounds and computer game beeps.
Also senses of movement have to be engaged. If you push against something it needs to push back. If I had three wishes for video games I'd wish that analog thumbsticks could push back. But for now this means the avatar/perspective needs to be pushed back, it can't merely glide around obstacles like metal on metal.
Textures and suggestions of smells and tastes are very important, but our technology is heavily biased toward audio/visual cues. Still what makes me hopeful is that all of these things are really very easy to accomplish with computers. Still no game that I know of does them well, especially movement is very impoverished even though it doesn't present any hard problems and you can reckon around it just by getting out of your chair and doing some simple kinesthetic experiments with your own body.
Graphically when I look at contemporary games I see glitches everywhere I look. I think if only there were fewer things on the screen at least there would be fewer nagging glitches. One last thing that I find essential to immersion is believability. A shallow reading of this word looks something like the article featured in the OP. But I mean something very different...
Early video games are really feats of design. Something like Donkey Kong isn't supposed to make you believe you are rescuing a potential love interest from a King Kong, still it's an expression of values of design, so it is intricately designed like a mechanical monument to its designer's brilliance. Consider what reality would be like if that was the case? Everywhere you looked you'd see so many coincidences that you'd soon conclude that your world was made by a shrewd watchmaker, and you'd begin to be suspect of their intentions. That's fine if an oppressive atmosphere is what a game seeks to deliver, but if not this kind of over "level-design" instantly breaks immersion. Why should there be a reward at every mountain top? The inverse of this is often explained as game design 101. This is immersion poison. Immersive worlds are chaos, they don't reward, they punish. Walk a hundred yards down an empty corridor, and what do you find? A dead end? There must be something here, why would there be a dead end? So you keep looking, and looking, and looking, well you've been playing too many video games. This is in fact a dead end, and that is how immersion works. I'm not sure we are all ready for immersion, but it's kind of the reason I am so passionate about video games, second only to my frontiersmen curiosity, third to my supreme devotion to media, fourth to ensuring I'm never bored out of my mind for even a second