With videogames, you can't adapt the core of the experience (interactivity and the way the game is built around it - the feeling of playing a game) in most cases, you can only adapt the overall concept and movie-like aspects (and novel spin-offs and adaptations are not really rare). This means, going beyond the usual shortcomings of 90%+ of book to film adaptations, there's going to be a lot of differences and adjustments. However, to contradict myself, I don't think this is a really problem (if anything, it makes it less of a problem) when it comes to adapting something, especially the games which are already movie-like in tone (more so Mass Effect, Uncharted than the uniquely videogame-ish MGS).
In the end, good director, good script, and good overall production will make a decent to good movie (or show?), maybe even a unique movie (since there have been middling videogames adaptations, they are not all garbage, aside from not staying true to the source). It doesn't seem to be the case that there are passionate creatives chasing after this idea (Max Landis aside...), so you are left with a sort of corporate view of "how do we make money from this property" slap-dashed into multiple failed productions and disappointing results. Disney can pull it off with Marvel comics, because it has created a dedicated, formulaic machine of shitting out decent to good movies at a breath-taking rate few others could challenge.
EDIT: For example, the Assassin's Creed movie being boring and lifeless, if critics are to be believed, has nothing inherently to do with it getting its setting and concepts (loosely, very loosely) from a videogame. It may have something to do with creating the conditions that would make it that way though.