Yes! You read the title correctly. I'm astounded by what I have found, and please 'listen' carefully. Are you tired of all the Mac Racism, and how you cannot make levels on Mac? Look no further!
All you need for this, is a Mac, and the Era Tileset.
1. Get 'Tiled'
Tiled is a free game level editor for all types of computers. You will be prompted with a message telling you to donate.
I do suggest you do, but it is not necessary. After you are finished downloading it, double click it, press open, and 'yes'.
2. Open Tiled
You will now open Tiled. What you want to do now, is press on this image on the top left hand side.
3. You will be prompted with a box. Place all settings in as I show you now. This is very important!
You may also change the 'width' and 'height' to 16px. I actually recommend it highly, as this is the same as Era's setting.
4. Download the Era Tileset. This is very easy. Just download this image to your desktop.
5. Add the Era Tileset.
Now, on the top left hand corner, press 'map'. . After that, click on the first option: 'New Tileset'.
You will now receive this box. . Locate the Tileset you downloaded and add it to the 'source' section. Leave everything else on the default, but name it whatever you want. Now press 'ok'. Please note, that if you chose 16px for the width and height, it will say that the height is 16px and so will the width. Do not change it to 8px.
Congratulations! You should have the tileset on the right hand side now. Do whatever you want, and make beautiful levels! This is something I messed around with on Tiled.
-Terry