The urge to collect all the items, achievements or secrets in a game.
"The game is essentially centered around collecting every vehicle, "Cool Version", and map. A good chunk of this can be skipped with the $10 purchase."
"You are encouraged to complete every level, every event, and collect every character."
"A small amount of gems (premium currency) is given for each hero per evolution level and each piece of equip when you obtain them for the first time. Gems are also given when you complete certain collections of heroes in the game."
"The main goal of the game is to breed and collect as many dragons as possible."
"Not really, but some dresses only fit certain accesories, which are near impossible to match on another outfit. It feels like having one shoe instead of a pair."
"Recruitment-exclusive Operators are especially hard to get, which keeps even veteran players logging in to start those timers."
"Dupes are the main way to power up heroes, so you end up collecting them all and seeking out as many copies as possible."