"Open All" is unlocked at VIP Lv.4. If you are unable to open all Guild Gifts at once, please check out your VIP level.
Your VIP level is displayed at left upper side of your screen. Also, VIP Points can be obtained from Daily reward, and also purchase VIP Points with Crystals through tapping "+" button.
TIP) Aside from opening all Guild Gifts at once, various benefits will be given based on your VIP level! Check out the benefits through tapping the arrow icons at VIP pop-up.