STEINS;GATE on Steam
store.steampowered.com
Developed by 5pb. and Nitroplus, STEINS;GATE was awarded Famitsu magazine's coveted annual Game of Excellence award and was voted one of the most emotionally charged “tear-inducing games” ever made, in a Famitsu poll.　It is a gripping and moving Visual Novel, which has already spawned manga and anime adaptations.

Date coincides with Steam summer sale, so is probably part of that.