Every game you play, you win free coins, even if you lose!
Winning a Game
coin_large_image coin_large_image coin_large_image
Win a game and you will rewarded with a number of coins.

• Win vs 1 Bot = 3 coins
• Win vs 2 Bots = 7 coins
• Win vs 3 Bots = 16 coins
• Win vs 1 Human = 5 coins
• Win vs 2 Humans = 12 coins
• Win vs 3 Humans = 20 coins

Finding a Gem
green_gem red_gem
Whenever you win a game there is a chance that instead of coins, you could find a rare Green gem, or an even more valuable, ultra-rare Red gem (worth 30 green gems). Gems can be used to trade for individual cards direct from the Library.
Losing a Game
If you lose a game, regardless of its type or number of players, you will always win a coin.
Hand Grenade
If one gets this card early, it somewhat functions as a removal option for weaker monsters that may have some annoying stats you want gone.  However, as the text suggests, this is not a removal card.  This is a card that inflicts 5 damage to a creature.  Threats that you may want gone can easily survive a hit from this grenade, and can still be a problem card, especially if it could regenerate by whatever method.  It's more worth it to make the room and spend an extra resource for fatal blow for 4 resources.  Or Imperial assassin and it's assassination effect.

but still, if you happen to get this card early, it can still function as a removal card, until decks start getting more advanced from players or bots.  Then it's time to look at other options.