Taking every hit on purpose
Some damage feels worth it for a reward. Often it is not.
A heart lost now is a heart missing at the boss. Skip a dangerous room when the payout is small.
Spending resources with no plan
Keys, bombs and coins run out. Spending your last key on a weak chest leaves a better one locked.
Plan how many of each you need. Save one for the door you have not seen yet.
Grabbing items you do not need
Not every pedestal is an upgrade. An item can clash with your build or replace a shot you rely on.
Pause before you pick it up. If it fights what you already have, leaving it can be the better play.
Ignoring your health
Your health is the run’s clock. Walking into the boss at low health removes your room for error.
Heal before the boss, not during it. A shop heart or a soul heart can reset your margin.
Next: How a run works and Floor routing.