Both animes are about the main characters trying to change the world through unnatural means (Death Note / time travel). The protagonists Light and Okabe are both geniuses, but while Light is a self-confident evil mastermind, Okabe is a good-hearted 'self-proclaimedly mad' scientist with a fair bunch of ridiculous inventions. Both have clever plotlines that will always keep you on attention and at the edge of your seat, wanting to learn more.
Steins;Gate are similar in the way that they both require critical thinking and your absolute attention for a clear understanding of what is really going on. Both these anime"s are dark, though Steins;Gate starts of with a lot of humour.Also, the voice actor of the main characters are indeed the same.
Death Note and Steins Gate are very close in nature, you got the whacked out kind of genius in both series, and both main characters love playing with fire (figuratively speaking). If you're looking for an anime that has psychological thrills and don't feel like watching all of code geass these are some good options.
I am a big fan of animes that require intelligent thinking, whilst the plots are not even similar, they both have a large sense of mystery as well as the ability to engage your mind! Both insanely brilliant animes that you're missing out on if you haven't watched them! Highly recommend on both sides.
Both shows have characters of great intelligence. Both have characters that mess the laws of nature. DN with a god and this Steins;gate with a time machine. Finally, both shows aren't very gory. They show blood on occasion, however it isn't everywhere and their deaths aren't shown. In my own opinion, they are very interesting shows. Each have unique characters that makes the shows what they are, and I enjoyed them.
Both series share a unique kind of way of looking at things.
Both take place in present-day Tokyo and the protagonists of both rely on strategic thinking in order to accomplish their goals, chiefly by discovering and exploiting the rules of their newfound devices. Both also cover similar themes, such as "be careful what you wish for" and the ethical implications of a human having control over supernatural powers (for Death Note, it's whether one should have control over life and death; for Steins;Gate, it's whether one should have control over time).
Ones a little more SciFi, the other is a little more Fantasy. Either way, chances are, if you like Death Note you will like Steins Gate.
Both center around brilliant, eccentric individuals who are tasked with unraveling mysterious occurrences.
Steins Gate is a little more light hearted with more lovable characters; But, both have HIGHLY engaging plots for the curious sleuth or scientist in all of us.
The two anime are thriller wich have a lot of suspense.