For Advanced Play
Once you master the basic rules, variants for a more challenging game:
You may destroy opponents' tower tiles in addition to walls. Like with destroying walls, the tower tile must match identically.
At the beginning of your turn, you may draw your first tile from the top of the discard pile. The second tile must still be drawn from one of the face down piles.
The last tower or wall tile placed into your castle must match on both sides, not just one.
Alternate Game Versions
Test your "fortress fortitude" by trying these other ways of playing. The above rules apply in addition to the following rules, unless noted.
If you make a successful attack in a two-player game, you may use the destroyed tile(s) in your own castle on subsequent turns instead of discarding the destroyed tiles.
All players build two castles. Win by finishing both of your castles or by destroying all your opponents' castles. Players may interchange tiles Between their two castles during their respective turns.
King of the Castle (for Two Players)
Both players build onto a single castle during their respective turns. As in the regular game, players may use their tiles to destroy matching tiles. The first player to complete the castle wins.
This is a one-player game. Deal yourself four tiles. Then turn over another tile from the draw pile to start your castle. (The "wall or tower first" rule does not apply, so a keep may be placed first).
Draw one tile at the beginning of every turn, then play tiles from your hand as in the standard game, discarding down to four.
At the end of each turn, turn over two tiles from the draw piles. If either matches ANY tile currently in your castle (including the keep), matching tiles are destroyed along with any adjacent ' same-colored walls or towers. (If a tile matches more than one tile in your castle, choose which tile to destroy).
Win if you are able to build a complete castle before the draw piles are exhausted. Lose if at any time your castle has no tiles, or if your castle is unfinished when the draw piles are exhausted.