I also want to know this.
We don't know ANYTHING about the number of levels or worlds in the game.
However we can make assumptions. For example, there's one stamp per level, and GameXPlain counted about 80 visible patches, but also mentioned that there are some patches covered up by something (I forgot what it was), therefore, it could be closer to 95 stages.
If we assume 8 worlds, then there's an average of almost 12 stages per world, which is actually too high (for an average), therefore, I'm going to assume there are more than 8 Worlds.
We don't know ANYTHING about the number of levels or worlds in the game.
However we can make assumptions. For example, there's one stamp per level, and GameXPlain counted about 80 visible patches, but also mentioned that there are some patches covered up by something (I forgot what it was), therefore, it could be closer to 95 stages.
If we assume 8 worlds, then there's an average of almost 12 stages per world, which is actually too high (for an average), therefore, I'm going to assume there are more than 8 Worlds.