Given that Bismuth Mindrender has Menace, the chances of it dealing combat damage to a player are high, especially if the defending player barely has any creatures to block with
Getting to tap down your opponents team is a nice effect to have, but not one worth playing without wanting the other mode
Then, once it's solved, it gains the ability to sacrifice itself to let you cast creatures from your graveyard for the turn
Tooltips are handy to remind players of the function of different keywords on the card
Gunk Slug is a neat design thats so frustrating to play against (I think its based on custom cards once played at a convention by Richard Garfield, though it mightve been Rosewater)
You can then cast that card for as long as it's exiled, though you have to pay the mana cost, colors, and all, which is why the Treasure tokens are so important with Rev