So, you want to convert your old (or new!) pack of .lvl levels to new-formats NeoLemmix, namely the .nxlv format, so that they can be played in NeoLemmix or SuperLemmix.
There are a number of ways this can be achieved, but here's the way I do it. Everything you need for this method is attached to or linked in this post:
1. Create a backup of the .lvl levels that you want to convert
2. Create a New Folder on your Desktop and name it "Converted Levels" (or something you'll remember later)
3. Move all of the .lvl files that you want to convert into the "Converted Levels" folder
4. Open the NeoLemmix 12.9.4 directory (
download it here if you don't already have it)
5. Move your "Converted Levels" folder from the desktop to the "levels" folder in the NeoLemmix 12.9.4 directory
6. Open NeoLemmix 12.9.4
7. Press F2 to navigate to the level select menu and select "Converted Levels" from the list
8. Press OK. This should load the first level, so hit Esc to back out to the NeoLemmix menu (you may get a "Could not find logo.png" error - just ignore this and hit "OK")
9. Once you're at the main NeoLemmix menu with your levels loaded, hit F8. This will run the Cleanse Levels process. You'll know it's happening if the scroller lemmings stop moving. Once the process is complete, a dialog box will pop up to let you know it's completed, and if there were any errors (hopefully there aren't! See
troubleshooting if you're having problems).
10. Go to the NeoLemmix 12.9.4 directory - there should new be a folder in there titled "Cleanse". Inside this folder will be a folder containing your levels in both .lvl and .nxlv format! You're done
11. (Optional) If you don't want to keep the .lvl copies, you can use
this purpose-built DuplicateDeleter to find and delete any .lvl files that have a corresponding .nxlv file in the same folder - this can save some time if you have a lot of them (particularly if not all levels were converted successfully)! N.B. This program only moves the files to the recycle bin, so they can be recovered later if necessary.