Finish any of the difficulty levels without dying and you'll get to play extra levels.

Beginner has 3. Not hard, but the last one is pretty cool looking.

Advanced has 5. Two of them are hard until you find the secrets, then they're not bad. The last one is a pain. Its like they thought level 30 was too wussy so they added a bunch of things and made it look damn_nice.

Expert has...yeah right like anyone could beat that without dying (no fair cheating!). I'll still try though.

Expert has 10 except you dont have to beat it without dying; just beat it without using a continue. If you beat the expert bonus levels without using a continue I believe, then you open Master mode which has 10 new levels.

If it opens a new mode, it could possibly be something different. The extra levels I'm talking about are part of the same game. YOu get sent right there after hte last level, still with your points, lives, continues, etc. Its as if Beginner has 13 levels and expert has 35.

This is just insanely hard!
Have any of you unlocked these?

I've beat beginnier and advanced without dying. I get to about level 7 on expert before I die. Only 43 more to go!

Its not really unlocking because you can't get back to the levels unless you go through without dying again.

Thanks! I've only seen the beginner levels so far, but I've only had my copy of SMB since yesterday.

I can get to Floor 26 in Advanced, but I used all 4 continues there.

Hard Hard Hard

But totally fun.

I just rolled a 300 in monkey bowling. Didn't open any new secrets up as a reward though. Oh well. Still looks sweet at the top of the score list.

Dont they become useable in Practice?

^^ Yeah they do. Any levels you have played including bonus ones become available through practice. Of course if you dont go through all the extra levels on the first run, you'll have to go through all of it to get to those last levels.