In RocksDX.pcx I see something that looks like a tube, but it is in a red rectangle... it's next to the pixeled time coin.
There also is a small color pallette on the bottom-right corner of RocksFontSmall.pcx.
And check out RocksSP.pcx... There are Murphy yawning sprites (player.bored?

Also in RocksMore.pcx I see something like a mask for the sand being digged... it's red.
In RocksElements.pcx: Next to the grey doors there are sprites of a brown door opening (MirrorMagic?) And right of the acid pool there is a smiley...

In the bottom-right corner there is a pixeled smiley this time, 80's Rockford and a lock (MirrorMagic again??) Above the sattelite, we have that grey ball again. Much things unused!