Diceies bases upon the NES game Palamedes.
The game can be seen as an "inverted" Tetris game with card game elements.
When you start the game, you have your empty playfield, and with time passes, a huge block of dices moves from the top of the screen in direction of the bottom. Once those dices hitting the bottom, you have lost.
But you have the ability to counteract those dices with your "Dice-Cannon". At the bottom of the playfield you have a movable dice, which can change the number on it, depending what you want it to be. When you now fire this dice at the corresponding dice in the dice-cluster, this dice will vanish and it will show in the line beneath your "Dice-Cannon". Once you have filled a combo there, you can use this combo to remove a certain amount of lines from the cluster.
These combos ranging from 3 of a kind/3 continuous/Black Jack (1 line) over 5 of a kind/5 continuous/3 Pairs (2 lines) to Straight Flush (5 lines). A Straight Flush for example means in this game that all six possible dices are in the combo with one of each type, in order from one to six.
If you have a combo combined, you are not forced to use it. You can just continue to try getting a better one.