In "Lego Batman," you unlock characters and special items throughout gameplay. In order to unlock Clayface and the Riddler in "Lego Batman," you need to complete the villain level "The Riddler Makes a Withdrawal."
Use Clayface to have him lift the Dumpster and move it. This will scatter Lego pieces--use these pieces to replace the wall lever and use it to open the window shutters.
Use the biggest truck in the parking garage to boost you to the Lego canister in the room to grab it.
Use a car to run into the orange booth in the lower right hand area of the parking garage to obtain another Lego canister.
Use Clayface to move the garbage truck to reveal levers that open the door, then step on the floor switches that appear. Leave the parking garage.
Make Clayface jump up on the metal bars of the awning to pull them down with his weight and allow him to use the fire escape ladder to get both him and the Riddler over to the left part of the screen and to the junkyard.
Unbury heavy objects using Clayface to get to one of the working vehicles and get it to the vehicle pad.
Mindcontrol the worker in the junkyard with the Riddler to get him to pull the lever. This allows you access to the other parts of the vehicle to finish building it and use the vehicle to get through the metal gates.
Drive to the right as you destroy objects along the wall until you get to the vent. Have Clayface tear it off the wall and build the ladder to climb up to the top.
Mindcontrol the man in the bathroom with the Riddler to get him to pull on the orange bar, dropping down a gargoyle statue which you will end up reassembling into a bomb.
Grab all of the canisters in the area--there is one in the alley, one on the lower left of the screen and one on a ledge up above.
Hop into the police car below and run into objects, releasing the pieces to build a detonator. Once built, jump on the red button to blow up the bomb and get into the bank.
Find the final Lego canister behind the solid wall that was blown away with the bomb and Sonic Suit it.
Unlock Riddler accessories with these codes: Riddler Goon: CRY928 Riddler Henchman: XEU824 Riddler's Jet: HAHAHA