Face of Fear: Igor would either get bigger or have a face like this

and all the enemies sprites would look like this

and they would all try to run away from Igor the best that they could, the bananas and tomatoes would jump away etc. It would be a bit like what happens after the second Quick!, except opposite.
Depressed Doll: Igor's bombs would be smaller, move slower, and effect smaller areas, and igor would get a depressed face.
Fat Doll: Igor would appear grossly overweight, move slower and be unable to fit into small areas, but he could kill enemies by jumping on them.
Coalman Doll: Igor's evil alter ego Coalman would appear, he is black, frowns, and uses black bombs, and chases Igor around, trying to kill him, sometimes when you kill Coalman, he drops a
Coal Lump: Once you get a lot of coal lumps, you can play a mode that is just like normal mode, except you are Coalman instead.