There's a moon phase switcher in the game. Beat an optional boss and the key is yours.

While the controls would be better on a touchscreen, I didn't have any problem with it using my mouse.
The lunar cycle is stupid but there's a "secret" room where you choose the state of the moon (and it doesn't count as cheating on your save file). That room is so easy to get to that it makes me wonder why they even bothered having the lunar cycle at all.

I enjoyed the game a lot because of it's art and music, but it's short, too easy and has no replay value at all.
Still worth checking out.

Yeah, already own it in HB5 bundle and don't really plan on playing it anyway. :-/

It's two evenings long at best, mostly because in the first evening you'll get bored enough to stop playing, but not bored enough to hate it.

But where's DEPONIA?!

it will never be released here.

Liar!