Check your story and game
Learning paths through this topic
Red marks in a number grid puzzle appear on the wrong cell or not at all
Players want a number the moment it clashes with another, but checking against the stored answer spoils alternative paths and marking only one of the two clashing cells confuses them. This entry shows what to compare, which cells to mark and when the grid counts as finished.
A full number-merging board is not always lost, and where the new tile goes
Ending the game the moment the board is full is wrong, and so is letting a new tile appear on top of an old one. This entry gives the exact end test, the choice of the empty spot, and the odds of a bigger tile, all repeatable from the numbers you pass in.
In a number-merging slide game each tile may merge only once per move
Slide a row of equal numbers and the result depends entirely on the order you handle them in: do it naively and tiles chain into one giant number, or the wrong pair merges. This entry gives the exact rule for a row, how to score it, and how to tell whether a move changed anything.
Pay offline earnings with a cap, and survive a phone clock set backwards
Welcoming players back with what they earned while away is a core pleasure, but the same sum can be farmed by moving the clock, and a negative gap can even take coins away. This entry covers the cap, the efficiency, and what to do when the clock has gone backwards.
After an update, old saves load into a scene that moved or is gone
You fix a typo, rename a scene or cut a chapter, and the people who saved yesterday cannot continue. This entry shows how to bring an old save to the nearest honest place in the new story instead of a crash or a wrong line.
Check that a single-use key cannot lock the player out of the game
If a key is used up and there are two doors, the player may spend it on the wrong one and have no way to finish, without any warning. This entry shows how to test every order of moves for such a trap before a player finds it.
Check that a drawing puzzle can be traced without lifting the finger
A puzzle that asks the player to trace every line exactly once only works if the picture allows it, and a made-up shape often does not. This entry gives a quick test for any shape, tells you where the player must begin, and names the trap that fools the obvious test.
Tell the player a row of a picture puzzle can no longer work
In puzzles where number clues say how many filled cells sit in a row, players mark a wrong cell and only learn it twenty moves later. This entry shows how to check a half-filled row against its clue at once, even with cells still unknown.
Count a daily play streak fairly, with a freeze for a missed day
Counting consecutive days sounds like adding one, until a player plays twice in a day, skips one, or a phone clock jumps. This entry lays out each case, how a stock of spare days covers a gap, and how to stop the streak from being earned or lost by accident.
How many different playthroughs does my branching story really have?
Ten small choices that rejoin do not make ten stories, and they do not make a thousand situations to test either. This entry counts both numbers, so you know whether to test every road or only every situation a scene can start in.
Producers with their own timers: count finished rounds while away and keep the leftover
When each producer finishes a round every few seconds, the time away has to be turned into whole rounds, and a lazy sum either pays too much, too little or throws the half-finished round away. This entry also covers producers that wait for a tap before paying.
Check that a timed quest line can be finished in some order within its days
Quests that need days, depend on each other and close on certain dates can quietly make a game unwinnable on the first playthrough. This entry checks every order and tells the AI either a working plan or that none exists.