📦 Do not try to restock weapon stands while the shop is actively open to customers. Shoppers might grab items for free before you can finish pricing them due to interface delays.
🏃♂️ Fighting enemies in wide-open outdoor areas is generally much safer than fighting them in tight, claustrophobic corridors. Use the space to dodge incoming projectiles and funnel enemies in a line.
🎯 Your default starter pistol features unlimited ammunition and is surprisingly reliable. Many of the heavier weapons you find have limited ammo or require button presses for every single bullet reloaded. Rely on your starter weapon for weak, isolated grunts to save your high-DPS heavy guns for bosses and massive waves.
Running a profitable black market store is your primary source of progression.