Yes. Trophies can be unlocked by a group or in solo.
It's normally best to buy all weapons by a group to unlock this trophy, to achieve this trophy effectively, follow this method:
- Be fair when opening doors, each player should take turns to spend their points when opening doors.
- Be prepared to gain many points before going out to buy all weapons.
- When ready to buy all of the weapons, use a grenade on a group of zombies (when near to end of a round) and make them legless which will leave you precious time to save running around to buy all weapons (including you and your friends/team mates to spend points towards the doors).
You may need about at least
10,000 roughly to spend on doors, and at least
15,000 (from what I remember ages ago). Which comes a total of between
The Collector trophy does not require upgraded weapons or weapons from the mystery box.
This may be quite hard to achieve unless you have a good motivation of escaping and surviving from a large swarm of zombies and also taking them down, be sure to make good use of your grenades for high points when used against a swarm of zombies!
Optional: If you may want to test your luck, you can use the mystery box for a good, powerful weapon like the Alien/Ray gun could wipe out a lot of zombies in a few shots (better when upgraded) which will make you kick ass!
Tip: Don't camp. :)