Mistake one: too many weapons
Players grab every weapon they are offered. Each one splits the upgrade rolls, and the core weapons never reach the level they need.
A cluttered build feels busy and plays weak. Fewer, deeper weapons win more runs than a long shelf.
Mistake two: ignoring the timer
The run ends on a clock, not on your comfort. Players who drift without a plan hit the boss underleveled.
Pick with the clock in mind. Every level should push damage or survival, not a pet stat.
Mistake three: late swapping
Swapping to a flashy weapon right before the boss is a classic loss. The new weapon is underleveled exactly when you need it most.
Build on purpose from the start. The weapon priority page shows what to grab and what to skip.