Games like 突然*恋人
Games like 突然*恋人 include 魔女的夜宴, ATRI -My Dear Moments-, Otome Riron to Sono Shuuhen -École de Paris-, Koi x Shin Ai Kanojo, and Love Is All Around. We matched them by the tags players give 突然*恋人 on Steam (Casual, Adventure, Interactive Fiction, Sexual Content, and 2D Platformer): closest matches first, and among equally close ones the better-known games.

魔女的夜宴
Shared: Sexual Content · Interactive Fiction · Casual

ATRI -My Dear Moments-
Shared: Casual · Visual Novel · Dating Sim

Otome Riron to Sono Shuuhen -École de Paris-
Shared: Casual · Adventure · Interactive Fiction

Koi x Shin Ai Kanojo
Shared: Casual · Adventure · Sexual Content

Love Is All Around
Shared: Sexual Content · Dating Sim · Interactive Fiction

Doki Doki Literature Club Plus!
Shared: Sexual Content · Dating Sim · Visual Novel

The Hungry Lamb: Traveling in the Late Ming Dynasty
Shared: Interactive Fiction · Adventure · Visual Novel

Summer Pockets
Shared: Adventure · Casual · Visual Novel

Senren * Banka
Shared: Casual · Dating Sim · Visual Novel

Tricolour Lovestory
Shared: Sexual Content · Casual · Dating Sim

Hamidashi Creative
Shared: Casual · Adventure · Sexual Content

月に寄りそう乙女の作法
Shared: Casual · Adventure · Visual Novel

Vampires' Melody
Shared: Casual · Adventure · Interactive Fiction

Lay a Beauty to Rest: The Darkness Peach Blossom Spring
Shared: Adventure · Interactive Fiction · Visual Novel

Aonatsu Line
Shared: Casual · Adventure · Interactive Fiction

Some Some Convenience Store
Shared: Casual · Sexual Content · Dating Sim

Florence
Shared: Casual · Adventure · Interactive Fiction

Mirror 2: Project X
Shared: Interactive Fiction · Casual · Visual Novel

Hatsuyuki Sakura
Shared: Casual · Adventure · Interactive Fiction

LoveChoice
Shared: Dating Sim · Story Rich · Casual

Knowledge, or know Lady
Shared: Sexual Content · Dating Sim · Interactive Fiction

Clover Day's Plus
Shared: Casual · Adventure · Dating Sim

NEKOPARA Vol. 2
Shared: Sexual Content · Dating Sim · Visual Novel

Aokana - Four Rhythms Across the Blue
Shared: Casual · Adventure · Visual Novel