To get the golden wreath, you'll need not only all the treasures, but also the intensity gates. According to this guide, the listed treasures and intensity gate are:
The third room...tempts you with a sometimes accessible treasure chest. If you want it, just be sure to watch the floor and the wall to get your timing right. Falling down hurts.
The next room contains an Exo Tank. You can simply drive it to the other side of the room, but you can also go around and destroy enemies by simply running them over. You can also use the tank's boost ability while climbing up the ramp to get on the floating platform. Get off, and food and a treasure chest will appear.
...a few rooms after that has one that contains trampoline floors. Be sure not to jump off of a platform. If you stick to the right, you'll find a Level 4 intensity Gate.
...Keep on attacking enemies from a distance to ensure safe platforming, and then travel carefully. Next up is another Exo Tank section. Eventually, a ramp will appear. Go up it. If you boost at the very end, you'll land higher up, and will be able to open a treasure chest.
The final trial is a room with invisible walkways. ...At one point, you'll be able to go left instead of forward, and can grab a treasure chest.