Merge Multiply Crush Balls is a merge game that features pachinko and brick-breaking elements. Across levels, the player upgrades balls, known in-game as bullets, and pins to create scenarios in which the balls break stacked numbered blocks. Their goals are to earn coins and perform upgrades for as long as possible.
The player uses an initial bank of coins to purchase pin value upgrades. The top pins have a +1 value. The player can purchase an additional +1, represented by a golden ball, and merge it with one of the existing +1 pins to make that pin have a value of +2.
When a bullet drops from the pipe onto the +2 pin and bounces around, its number and striking force increase. It then strikes a box with the equivalent force. For example, if a +1 bullet drops onto a +2 pin once, it drops onto and strikes a box with a +3 force. Every time the bullet hits the box, the number on the box decreases by three points. If the bullet bounces two times against a +2 pin, then its value becomes +5 (i.e., 1 + 2 + 2) and decreases a box number by five points. The value changes based on the number of bounces.
Merge Multiply Crush Balls then drops bullets into colored vertical multiplier slots that can multiply the player's coin winnings up to five times. The coins then auto-transfer to the bank in the upper-left corner.
Before starting a new level, the player chooses to upgrade the bullet count (i.e., the number of bullets that drop), the bullet number (i.e., the starting number on each bullet), or the shoot rate (i.e., the speed of the drop). They can only select one of these options per level.