Extra Slots

Extra Slots is a type of upgrade that comes in two difficulty levels. The first one is a super easy difficulty level, and it can be obtained by being inside the game for a total of 15 minutes. Once unlocked, it will allow the user to fit an extra 5 pets in their inventory.
The second Extra Slots upgrade is an easy difficulty level. To unlock it, the player must be inside the game for a total of 50 minutes. Once unlocked, it will grant the player an extra 10 slots for pets in their inventory. This does stack with the weaker Extra Slots ability.