I first discovered Bonus Levels on Area 2 Level 3 (2-3). Near the end of the level, I saw a cloud that went up and down. I thought I would jump on the cloud and see what happens. It went higher into the sky (where I couldn’t see the sun) and took me to another cloud with a sign with a “?” mark. When I jumped on the cloud it took me to another level in the sky. This was the Bonus Level!
The way you do it is by jumping from cloud to cloud collecting items (like coins, hotdogs, and extra lives) while the timer ticks down. (You can click the image to the right and see a larger picture of one of the bonus levels). If you miss the cloud, you fall through into the next level. But if you make it all the way to the end, Dylo does his victory dance! And then you start the next level.
I’ve found several other bonus levels, but I’m sure there are other ones (hidden like secrets) that I haven’t seen yet. If you have found some, post a comment so that others can find them too!
See you in Dylo’s World!