Really like the visual style and theme of the cardboard! Really unique and great execution on the theme. Gameplay wise there is definitely a good core to it, however I ran into some trouble fairly quickly. I'm not sure if the cave walls are meant to be drilled through or not or if I just needed more upgrades to the drill, but I managed to get stuck with no way to return to the top or reset, which is a shame because otherwise I was enjoying exploring the caves and drilling!
For some more in-depth feedback you can watch my gameplay playtest here: