Stages 23 and 24.
Stage 23- This stages requires some timing especially if you want to avoid enemies. Most of the doors are located on the far side of wall without ladders or pipes to dodge enemies coming to you. Use the lighting bolt to eliminate enemies. It’s possible to dodge Dark Foghorn at the top right to access a key but he can turn back and I was lucky to have quick reactions to drop a bomb.
Stage 24- A 1UP carrot was added and an additional way to get a key above Yosemite Sam. The hammer is hidden and I was able to eliminate all 5 enemies on the bottom part. Bonus! I got Dark Daffy to hold onto the tightrope and look at what happens!