Grimace will tell you that he saw Hamburglar pass but did not know where he was headed. He will then ask you to find at least three cards from his puzzle. If you give them to him, he will let you access the levels next to the lake, where you can find more.
Level 1 - Cliffton Heights
Climb the clouds on your right, to reach the top of a mountain. Here, take a long jump to the left to reach another cloud, with a card at the end. Take the card and go back. This time up the mountain, run quickly to the right, crossing the crumbling bridge and taking a long jump to reach other clouds. By jumping on these clouds you will come to a zipper, which will take you to a bonus level. Jump onto the rightmost springboard to crash into the ceiling and reach two 1-Ups. After getting them, jump on the springboards again, where the arches are. Once you have gone up, you will not be able to descend any more, so try to take as many arches as possible. At the top you will find the zipper to return to the main level. Continue to the right. At the base of the tall and narrow hill there is another 1-Up. Further to the right you will find the finish line, with some springboards on it. If you jump correctly, you can go to the right of the finish line and take the Golden Arch.
The card you found is for Grimace’s Higlands.
Level 2 - Moose Bridge
As soon as you start the level, slip into the small gap on the left. Go down and proceed to the right, paying attention to the crumbling bridges. You will find a card. Take it and go back to the beginning of the level. Proceed to the right, crossing the two bridges. You will then have to overcome two other crumbling bridges, with some blocks missing. Under the second one you will notice a springboard. You will have to move carefully, to make the blocks above the spingboard fall, without falling yourself. You can then use the springboard to jump to the top right. You will now have to cross two long crumbling bridges, with many blocks missing. If you succeed, at the bottom you will find another card. After taking it, you will fall directly to the right of the finish line.
The first card you found is for Grimace's Highlands, while the second will turn out to be a secret card!
Level 3 - Lumberjack Lane
Proceed to the right, always jumping on the top of the trunks. Immediately after the fifth trunk, however, drop down. You will find a card. Take it and then return to the top of the trunks. Keep jumping to the right, until you notice a block to the left of a branch. Grab this block to uncover a springboard. Use it to jump high. Climb as far as you can, even going over the top edge of the screen. Carefully jump to the right on the trunks, without falling. Eventually you will find another card. After grabbing it, take a long jump to the right to land to the right of the finish line.
The first card you found is for Grimace's Highlands and the second is for Professor's Workshop.
Level 4 - Fry Kid Falls
In this level you have to be careful not to end up in the lake at the bottom, where the deadly fish Gnash awaits you. In the first precipice on the right are two 1-Ups, don't take them both or you will fall down. Going down the second precipice, you can reach a zipper with a boat. This will bring you to a bonus area. In this level navigate to the right with the boat, paying attention to the fishes. When you get to a shoal, grab the boat and take two long leaps to the right, onto the platforms. You can then place the boat on top of the waterfall and go inside. This way, you can collect all the arches above and a 1-Up, before returning to the main level via the zipper. Go back upstairs and keep going to the right. You'll find two more 1-Ups in the next precipice, but watch out for Gnash! Then drop into the third waterfall on the right to find another 1-Up. After this waterfall, continue to the right, always remaining on the higher platforms. This will bring you to a lift: jump on it to make it move. Remain still on the lift until it arrives above the finish line. Jumping to the right you will find a card. Collect it before crossing the finish line.
The card you found is for Grimace's Highlands.
Now you already have four Grimace cards. Go back to his house and Grimace will let you access the lakeside levels. He will tell you to find a total of 5 cards now, after which he will show you the way to Professor’s Workshop.
Level 5 - Danger Lake
Jump into the boat and sail to the right paying attention to the fish. Use the shoal to pull up the boat and throw it into the next lake. Climb the steep green slope and jump on the lift in front of you (there are only arches to the left). The lift will descend slowly: when it is about halfway down, jump to the right. Grab the fill-in block you find and go back. If you got off the lift at the right time, you can use it to jump to the left. Climb as high as you can to find a dotted platform. Place the fill-in block and jump on it. You can then jump to the right and reach a card. After grabbing it, get off and climb onto the crumbling bridge. There is a boat below the bridge, so let the bridge crumble and jump inside. Navigate to the right. You can use the bridge and the two springboards you will encounter to take a long jump to the right and land to the right of the finish line.
The card you found is for Grimace’s Highlands.
Level 6 - Far Falls Forest
To collect all the cards in this level, it is best to face it twice. At first, at the beginning of the level, jump to the left, without touching the left edge of the screen. If you have jumped correctly you will end up on a trunk with a zipper, otherwise you will fall into the water and you will inevitably be bitten by Gnash, losing a life. Enter the zipper and you will be transported onto a card: collect it. The finish line is right above you - tap it to complete the level.
The card you found is for Ronald’s Clubhouse.
Note: at this point you will have all six of Ronald's cards. If you go to his house, Ronald will open the bonus world “Puzzleworld” as a reward. However, Ronald will tell you that before you can access the levels of this world, you will need to find all six secret cards. By now you only have two, so go back to level 6 of Grimace's Highlands.
This time continue to the right, jumping on the trunks and avoiding falling into the lake, where Gnash awaits you. You will notice a boat on a branch, grab it. A little further to the right, throw the boat into the lake and jump into it, to cross the lake unharmed, still paying attention to the fish. At the end of the lake you will have to pull up the boat and throw it into the next lake, taking advantage of the shoal. At the right end of the second lake, pull up the boat again. This time, however, there are no safe places, so you have to be quick and avoid getting bitten by Gnash. Then climb the trunks, taking the boat with you. You will come to the top of a waterfall. Throw the boat and jump into it, continuing to the right. This way, you can reach a card and a 1-Up. After getting them, carefully jump down. Keep jumping from one trunk to the other and shortly after you will arrive at the finish line.
The card you found is for Grimace’s Highlands.
At this point you will have all six of Grimace’s cards. Go back to his house. Grimace will let you proceed to Professor's Workshop.
Note: if you then go back to Grimace's house, he will provide you with valuable information, as a reward for having found all his cards.