can you actually only play the game once

[D-Man]

i missed some of the achievements but i respect this game and want to get all of them. is it because i took the shatter lightbulb ending, is there something extra im missing? i think i heard there was like a bonus chapter or something

[Poyau]

you didn't finished the game yet, an old friend wait for you
( for the achievements you missed you will be able to get them at some point )

[D-Man]

thanks for both of you guys, i got to play solstice AND get all my sweet sweet achievements