At some point I was thinking there should be a list of what the objects do, but eventually by the time I finished it, I had discovered that this explorative element actually makes up half the charm of it.
Maybe once the player completed all levels there might be an overview of the different items with a short description (as in the spiky things might be having a tag of "ouch! beware of these" that could still be somewhat cryptic about all of their mechanics).