I Ace and collect some of the currently accessible single-player Goodies in the "Subway" level. This level is unique in that it is simply impossible to get all of the single-player Goodies in one playthrough. It's possible with a minimum of two playthroughs, but it's generally easier to try to collect everything over three or four playthroughs. Alternatively, you could also use multiple players if you want to increase your chances of collecting all of the currently-accessible Goodies in one go.
If you really wanted to, you could grab the two striped Materials on the first elevator in a single playthrough. Grab the one on the left first (it's slightly higher), then quickly run to the right and jump up to catch the second one. I don't perform that action in this video because I must return a few times to get everything anyways, so I just pick up the second striped Material in a later recording.
If you're missing Goodies, make sure that you check the hidden area that can be found whilst riding the elevator down to the lower subway trains. It is very easy to overlook that location when playing through this level.
When I ran through the race in this level this time, I only picked up one Prize Bubble containing a Sticker. In case you didn't notice or know, there is also another Prize Bubble with an Object and a Challenge Key to be found within that portion of the level. While it is certainly possible to get those items (and to get two or even all three in one run), it's far from easy to do so. I'll show you how to get the remaining two items in a subsequent video.
Revisit: After getting the Intense Blue Graffiti Sticker in "The Construction Site".
I revisit the "Subway" level multiple times in order to collect the remaining Goodies and the Challenge Key. Then, I cover the Cooperative Challenge (and its exclusive Goodies) for this level.
If you don't remember for whatever reason, the Intense Blue Graffiti Sticker (used to activate the second of two Sticker Switches in this video) was hidden in the "The Construction Site" level.
Special thanks goes to the random online player featured in this video. He goes by the PSN ID of Abu_Yousef21.