Then, we're waiting the jam's end to add those new features. The only update we did since the submission was a fixing a bug that ruined our online leaderboard. Is it okay that we keep that fixed version as the original build?
We're thinking about uploading a new version with your idea of showing the ink. If not it, at the very least highlighting it with white or something to make it more visible.
About the SFX, @Matheus is our guy for sound effects. He's really good at recording those stuff!