Kaeri Yume (帰り夢)

Overview
Kaeri Yume (帰り夢, lit Return (home) Dream) is a Japanese Yume Nikki Fangame developed by Sute Inu A (捨て犬A) (aka garigaru (ガリガル) aka Matsuo Nitarou (松尾二太郎)), who also developed Hide&Seek.

Gameplay
You start as a girl named H2O, who is travelling in a bus. She can save by interacting with the cellphone on the seat next to her.

She enters her dream world by sleeping on the seat left of the cellphone. Leaving the bus after sleeping will lead her to the Nexus which has sign poles that connect to other worlds. You can wake-up by pressing the Q key.

Plot
The protagonist's name, H2O (the elemental composition of Water), is possibly related to the permanent rain in her dreams. She is stuck on her own in a moving bus, but it's unknown where she's going.