Thought I'd take Simon's advice and create a new thread for programming related questions.
I didn't create the SuperLemmini codebase, but I have looked through enough to make my own changes to it, and I'd love to help other people get started being able to do the same.
First step, you'll need the code:
You can download my fork:
https://github.com/Blazingstix/SuperLemminiTooOr you can get the original Lemmini:
https://bitbucket.org/fade0ff/lemmini/src/master/As far as I know Tsyu's SuperLemmini isn't on any source-control, however he has shared links to google drives with all his versions zipped up. I have also included those versions previous revisions in my SuperLemminiToo source.
Second step:You'll need something to edit and compile the Java code in. I recommend Eclipse, but I'm sure there are others.
https://www.eclipse.org/ide/Once you have the source code, and you've set up Eclipse, make sure you have all the proper dependencies hooked up. I've tried to include all the dependencies in my github (along with all their respective licenses and source code where I could).
SPECIAL NOTEIf you're using my SuperLemminiToo code base, you'll need to copy the /data folder into the /bin folder, for SuperLemminiToo to recognize it.
After that's all set up, and you're able to build the code, you're ready to start playing. I recommend looking through the code, or even running step by step through it.