I played ME 1 for the first time after parts 2 and 3 (I was a child and didn’t even know about the first one). I didn't get into the plot either. But ME1 is a kind of story of how the brave Cap Shepard, being an elite soldier, gets the opportunity to prove himself and, in addition, save the world from someone in whose existence they do not believe. On the one hand, the game is interesting, but on the other hand, not everyone will like it. For me personally, it is almost on par with part 3. It is inferior to 3 parts in one, and superior in another. There are also some unnecessary mechanics that they finally decided to remove, because if you play ME1 after parts 2 and 3, it will be very uncomfortable, taking into account the slightly different battle mechanics. In parts 2 and 3, everything is more, I would say, adult. But regarding part 1, there are inconveniences that you can turn a blind eye to if you like the series. My personal opinion: Mass Effect 1 is the beginning of a franchise that, when finalized, was turned into a gorgeous piece of candy.
Graphics are not the best
Shootings are close to ideal
The ability to make decisions here is the most advanced in the series.