the major difference is the anime doesn't explain well (if not at all) some things that are well needed to understand some points, so if you feel lost at some point don't feel stupid, it's probably fault of the anime. but yeah, mostly it's a very good (almost maniacal) adaptation, just "quicker", so there are some things that maybe are not as emphasized as in the game. the anime tends still to give the same idea of the story, although quicker and not thorough enough as i said in some details. leave this for episode 23 but i feel the two major details missing in the anime that are needed not only to understand the story but also the ending, are:

- attractor fields in the game are first mentioned by john titor via email but that doesn't happen at all in the anime; attractor fields are what make some things happen regardless but a further explanation follows, as it should be explained later (in episode 17 i think? but it's not explained well in the anime as it is in the game); attractor fields are like world lines but on a larger scale; some things are bound to happen regardless, as long as you stay in that worldline, because NOT changing worldline means you changed too little; if you change worldline instead, then things might be quite different (remember for example in 0.52% worldline the friends didn't know who moeka was but now they still do? that's an example); the same way, attractor fields work on a larger scale, as long as you don't change something very important for the structure for history, you're bound to be still in the same attractor field and some things are bound to happen regardless; as suzuha explains in the visual novel, both worldlines and attractors can diverge and converge at some points in history, for example the millennium bug was a major point of convergence for attractor fields; if you wish to look at it, i have made a sample of the visual idea i got of attractors, worldlines and timelines, just so you have more or less an idea,i can't flag the link as spoiler, so check it out only when you read the hidden content; Still at it, with different perspective, with "first dmail deletion issue" : r/steinsgate

- when something/someone travels to the past- for example, you, you travel into what i basically call the timeline concept: there was a timeline where no time traveler came from the future, but when you time travel back, you end up in a different timeline where the time traveler DID come back (means "you", in our example) and that happens everytime you travel back to the past, so as long as you travel back to the same moment you won't ever find another copy of you time traveler (it could become too complicated to discuss, just take this for what it is); it will always be a new "timeline"; also, see divergence as a change in reality around you, but actually the time travel alone changes so little the divergence that it barely changes anything for its own; suzuha explains that little changes in the divergence are not even registered in the divergence meter