For one week only, you can collect freebies to celebrate the 4th anniversary of Puzzles and Survival. There is a special "anniversary bubble" available on the last day. You must log in each day to collect all the gifts, but do not need to collect them every day. So long as you collect the gifts before the event ends (at reset of Ace Day 5) you can collect them all at once. You will find this event in the Gift Center.
How to claim...
If you have logged in for seven days during the event, you will see the Anniversary Bubble (permanent) with a glow around it when you navigate to the Anniversary Address in the Gift Center. Tap on it to claim it. Then go to your bag to activate it. You will find it on the Gadgets tap just under stamina and sticky bombs, if you have them. Tap on "use" then "confirm".