Critter Pop: how a robot helped tune 40 match-3 levels

Critter Pop is our match-3: match 3 identical critters. It has 40 levels in 4 scenes (farm, forest, beach and snow), with the critters from Kenney’s Animal Pack Redux (CC0), and menu, level select, pause and game-over screens in the same style as the rest of the studio.

Specials that combine

• +Four in a row makes a striped critter, which clears a row or a column.
• +An L or a T makes a bomb.
• +Five in a row makes a rainbow.
• +Specials combine: striped with striped makes a cross, bomb with bomb clears a 5x5 area and two rainbows clear the whole board.

Obstacles

Mud, ice, crates and cheeses that must reach the last row. Each level has up to 3 goals and gives up to 3 stars. A lesson learned early: ice or crates filling a whole row block the refill of critters below it, and obstacles under holes become unreachable, so the level generator avoids both.

The robot that plays

To avoid tuning 40 levels by gut feeling, we built a robot that plays each level and adjusts the number of moves and the 2-star and 3-star scores. On the first 10 levels the robot wins about 85% of the time, and about 70% afterwards. We still need validation from real players, which is what the tester sign-up is for.

On Android, the rewarded ad gives 5 extra moves when you lose (once per attempt) or lets you start a level with 2 specials. Version 0.1.1 fixed an achievement notice that covered the screen.

Critter PopgameMatch 3 identical critters: 40 levels with mud, ice, crates and cheeses, and specials that combine.see page →