This first area has a canister that you could see the first time, but were not able to get it. It is actually pretty easy to get on Free Play. Just turn into a super-strength character and push an object with orange handles towards the canister. Any jumper character should be able to grab the Third Canister in a few jumps.

For here, it is important for the characters to go to the right, and there is a lot of team playing. Harley needs to jump to a railing, then to a second level for a spinner. This will turn a door around, and Joker needs to be on the other open side of this door when Harley is done spinning it.

From here, Joker needs to go to the other end of a scale, and some walls upstairs will drop for Harley to go through. When Harley steps through, Joker needs to step on the other side of the scale, and Harley can go further. Harley can shoot or punch out the thing that has electricity coming out of it.

From there, it is about building two things. Harley needs to build a plunger for dynamite, and Joker needs to build the dynamite. This will clear the way to the next thing.

Harley needs to jump on a yellow platform, which will clear the way for Joker to pass through. Joker needs to step on a yellow platform that will raise up some bouncing thing. This needs to be done again as Harley automatically advances.

When you get past the one area where you need to constantly change characters to get any further, you will need to change into Sonic Batman and shatter some glass. Go into the room and get the Fourth Canister.

Go ahead and turn back when you get out of this area, and walk along the dock of that same aforementioned area. There will be a place that Mr. Freeze needs to use his mad skills on. Once it is froze, it will turn into an ice cream cone. Destroy the cone, and you will have one of three for a canister.

On the boardwalk there is a door that is boarded up. It needs to be broken, and then there is a shiny wall that needs to be destroyed with an explosive. Go in and take out the bad guys, and save Hostage 22/25. Go ahead and build a lever here, and you can pull it to get the Fifth Canister.