That game was made for 42th edition of the Ludum Dare. We were two people working on the project, and we used Unity3D (personnal license) to make it. We used Krita for graphics art.

Graphic arts and code were made from scratch, this is not the case for the sounds,  musics and fonts :

Fonts :     PixelSix by Cal Henderson (on dafont.com for scoring and Game Over)
Sounds :     Tamagotchi on GameBoy, Kaptn Blaubar Die Verruckte Schatzsuche on GameBoy Color, Falling Rock by Spookymodem (OpenGameArt.org)
Game Intro :     Green & Gray by Pugly (OpenGameArt.org).

Cause we're not professional in procedurally generated level design, you may be stuck sometimes. So be carefull, anticipate, and click "retry" if you are !