Where i can unlock all new characters?

[Katana Puffin]

I only found evil Rad in level 8...any others?

[McMarius11]

yeah i want to play this game with just duke and no one else :D how can i play with him

[Katana Puffin]

I remember Duke was in the first or second level

[Allard]

Originally posted by McMarius11:

yeah i want to play this game with just duke and no one else :D how can i play with him

You can find him inside one of the houses on the second level.

[TheMaverick]

Cosmo is in Level 4, after the first boss. In the house just right of the exit.
Bombshell is in level 5. When you find the waterfall with the 4 huge wheels in front, you have to go up the wheels and to the left, where you'll find ropes to swing from. Instead drop down and enter the house. In there Bombshell waits.