When someone you hold dear is met the fate of losing their life, and you have the ability to go back in time to that moment to try and save them, do you have what it takes to do it? In Steins;Gate, science is used to create a time a machine, rewinding the clock and changing the course of fate and time by saving the one life (or two) In Erased, it is a slightly more chaotic as there is no science involved, only a lingering sense of guilt and the ability to rewind the clock before a drastic event occurs.
These parallel lines were what drew me to Erased, and I wasn't disappointed. It did remind me of Steins;Gate with the aspect of time traveling to save a loved one. Changing the course of the present and time itself by making that one change and saving this one life, no matter the outcome. Hence, if you have enjoyed those elements in one of those anime shows, you will definitely enjoy watching the other.

-Both protagonists use their cellphones to change the future
-Both protagonists try to change the outcome of a future event to protect their loved ones
-Both include a female and male lead that try to interfere with "fate"
-Both have a complicated plot which plays with your mind

*P/S: Keep in mind that Mirai Nikki is a lot more twisted if you like that aspect.

Beginning with the obvious, both Re:Zero and Steins;Gate were animated by the same studio, White Fox and both main protagonists have time traveling related abilities.

Now for the juicy stuff, both Okabe and Subaru are quite different from the usual anime protagonist and aren't meant to be self-inserts for viewers. They both must overcome obstacles to save the ones they love and both feature thrilling story lines and engaging characters that break the mold of most anime tropes like Tsunderes (with Steins;Gate's Kurisu) and Moé characters (Re:Zero's Rem). The authors want you to see the MCs go through very difficult (and sometimes gory) hardships in order to reach their goals. In a nutshell both are:

- Animated by White Fox
- Time Traveling Related
- Have fresh Non-Self Insert Protagonists
- Mold Breakers of Anime Tropes

and both anime titles have a thing for colons and semi-colons.