Missing characters

[jumpman174]

I'm still missing the following characters. I have looked everywhere. Anyone have any idea where these may be? Thanks.

Sally
Maximus
Rockalot
Undead
Undead
Undead
Mart
Humphrey

UPDATE: I have found all of these characters. Mart was in the Meet the Devs level, the rest were in the final boss battle of the main campaign.

[sentury111]

I'm missing Matador and Howl. Got the rest. Playing the levels that they would most likely be in by the characters that they are next to but haven't found them yet.

Any tips from anyone would be great.

Thanks.

Edit: nevermind I found them. Howl was in one of the graveyard deathmatches. Matador was in Small Rooms. And Robot was in the Lost Levels about halfway through like another poster mentioned in another thread.

Now I just got to beat the final boss. I keep getting close then lose. Not that hard just keep messing up.