There's no obvious reason why Hakbal would be difficult to code in, or be less effective in a two-player game
But to win with it is slightly harder, and you'll need six types of permanents as well as five colors of permanents
GLEAM AND GLOW is the best healing effect in the game by a mile, allowing you to heal 3 damage (from a single character) and draw 3 cards
I haven't been following Standard closely since rotation, but I can definitely see this card coming in handy in many matchups due to its versatility
Providing a red mana for each Junk Token cracked, Rose, Cutthroat Raider essentially turns each one into a mono-red Treasure
For Mirror Box, that rule is the legendary rule that says you're only allowed one copy of a legendary creature card on your battlefield at the same time