The .zip file is missing the tile set. I went to mari0bros2's SMB remastered to get the tileset. However it results in many of the other levels (1-4, 2-3) becoming broken.
Updated and reuploaded, should work now.
Anyways onto the maps themselves: I'm sorry if I get two critical over these, but 1-1 looks like a very blatant SMB 1-1 edit. It may also be worth noting unless it's intended, the bone tiles you used to make the stems of the mushroom platforms are considered solid by Mari0, therefore I had to go over the mushrooms to continue through the level.
If your not critical I'll have trouble improving my levels. That's actually what all of world one was supposed to be, but now that I think about it maybe it shouldn't be, all probably fix that soon. The reason I chose the bones was because they were solid.
1-3: An easy part for Mario to get stuck if he's Super or Fire Mario, and Fire Flowers will spawn inside the solid mushroom, unobtainable without the Portal Gun. Some parts of this level felt like rehashes of 1-1, though after skimming over with the editor, I can see this is another "time progression" mappack where you play the same level multiple times as it advances through time.
Yeah kinda got lazy there, I'll probably fix that soon too! You can obtain it with the portal gun?! Yeah that's what it's supposed to be, If you don't like the fact that it's rehashed I could reorganize the levels. It wouldn't fix it but it would make it less noticeable.
I think I should bring up it's possible to upload things to Mediafire as a guest without an account. And I'd recommend making the levels from scratch rather than building off SMB1's maps. But I do see this map pack having high potentinal if executed properly.
Well, I signed up for a MediaFire account so it shouldn't be a problem.