Energy
Auto-buy keeps choosing the item that pays back fastest, even when it is out of reach
The best-value upgrade is useless if you must wait ages for it while a slightly worse one pays today. Here is a score that counts both the waiting and the paying back, so an automatic buyer feels sensible to watch.
Idle income earned while the app is closed should taper off and then stop
Paying full income for a week away makes the game pointless, paying nothing feels mean. Here is a way to pay in steps that shrink, stop at a ceiling and let an optional bonus double the result without breaking either.
An upgrade that finishes while the app is closed should pay from the moment it finished
A player starts a long upgrade, closes the game and comes back to a payout that ignores it, or pays the new rate for the whole time. Here is how to split the away time at each finish so the numbers are right.
Magic power refills while the player is still casting, so spells never run out
Energy that regenerates instantly makes resource management disappear: just keep casting. A short pause before the refill starts brings back the choice of when to act. The delicate part is a pause that ends in the middle of a frame.
A burst of adrenaline hides the tiredness, then sends the bill all at once
In a chase the hero should feel no tiredness, yet running forever at no cost would break the story. Here is how the tiredness is only put aside during the rush, how much comes back afterwards and what stops the crash from being unfair.
Several wounds bleed at once: how they combine, and how a bandage helps
Three small cuts should be worse than one, but not three times worse, and blood loss in whole points must not vanish when frames are short. Here is how bleeding sources combine, how fractions are carried over and which wound a bandage should close.
A dark bargain lends you strength now, and the energy you regain next goes to pay it
A pact that gives power at a cost is only a threat if the cost really lands. Here is how borrowed energy comes with interest, why recovery must pay the lender before the player, and what to do when the bar is nearly full already.
A cabin warms up while the fire burns and cools when the wood runs out
A survival horror night in the cold needs a temperature that reacts to the fire, slowly and the same on every machine. Here is how the warmth follows the logs, what happens when the fire dies in the middle of one frame, and why it must not jump.
A calming charm soaks up fear damage, but not all of it and not for long
A protective charm that blocks every point of fright makes the scary parts pointless. Here is how a temporary shield can take only a share of each hit, fade with time and stay under a ceiling, with the leftover reaching the real meter.
A found-footage camera should lose its features one by one as the battery fades
Night vision, recording and the screen all eat power, and a battery that simply hits zero is dull. Here is how the camera sheds features at set levels, why switched-off modes must stop draining, and how to show a number that never lies about being empty.
A protective circle of candles: when will it fail as they burn out one by one?
The circle holds as long as enough candles are lit, but they all have different stubs. Here is how to tell the player how long they have, which candle's end really matters, and what relighting one does to the answer.
Matches and a candle stub: when lighting should cost a match and when not
Every wasted match feels cruel in a horror game, but not every failure is the player's fault. Here is how to decide which attempts burn a match, how a candle keeps its wax between lightings, and what a draft changes.