Sure does! The manga of Steins Gate expands on the story and characters from the original source. It offers a different visual take on the popular series.
In my opinion, the Steins Gate anime doesn't ruin the visual novel. It might present the story in a slightly different way for the medium of animation, but both have their own merits and can be enjoyed separately.
Sure, Steins Gate 0 is a new story. It delves deeper into the aftermath and alternate possibilities of the events from the first Steins Gate, giving fans a whole new perspective.
In the Steins Gate visual novel, the story progresses by following Okabe Rintaro's journey. He discovers a way to send text messages to the past, which alters the timeline. Each time he sends a message, different events occur in the present. For instance, at first, his actions seem to lead to small, strange changes. But as the story unfolds, more significant and sometimes disastrous consequences start to surface. His relationships with other characters also change based on these time - travel events, which in turn drives the story forward as he tries to fix the messed - up timelines he has created.
The Steins;Gate visual novel indeed has multiple endings. These endings vary depending on the decisions you make during the gameplay, adding to the replayability and depth of the experience.