Create a gameplay loot in a...

Create a gameplay loot in a free-to-play mobile extraction shooter game, where players acquire money and materials from the game, and they can upgrade their guns/abilities outside.

Guns: They can be leveled up by merging the same guns together.

Abilities: Players can become stronger in these ways:
basic stats (hp, atk, movement speed, etc)
jetpack: players have a jetpack to help moving around
loot: traits that help players loot better
other traits or passive abilities are also ok