Similar plot device for time travel, small little sphere object, both have stunning visuals, although the art seems more original for toki wo kakeru shoujo because Uchiage Hanabi, Shita kara Miru ka? Yoko kara Miru ka? is super similar to the monogatari series, even for the studio being the same, the main characters are almost the exact same of the monogatari series.
The Girl Who Leapt Through time did much better at executing the time travel and romance aspect, the romance between Nazuna and Norimichi basically consists of them falling in love in literally 1 day, and the romance between makoto and chiaki is very wholesome, they've known one another longer and makoto tries to deny chiaki and uses time travel for that, meanwhile norimichi uses it to keep trying to be with nazuna.
Overall though the resemblance is there, however, the Girl Who Leap Through time is far better.