The tooling and infrastructure in this project are pretty interesting as these things go. It's always cool to see how each decompilation project springs up with different ideas and goals - this one seems very focused on 1:1 accuracy, with a side-project for compatibility / cross-platform reimplementation:

* https://github.com/isledecomp/reccmp is a lint tool which compares compiled function reimplementations with the original binary and produces an automated report detailing the instruction level accuracy of the re-implementation, while dealing with all of the fun of C++.

* https://github.com/isledecomp/SIEdit is a resource editor for the bizarre RIFF-esque resource streaming format the original developer (Mindscape) seems to have invented.

Also while we're on the subject of vintage LEGO games, I've recently been quite into playing Manic Miners, a complete Unreal Engine remake (not decompilation/reimplementation, an actual ground-up recreation!) of Rock Raiders.

I'm hoping someone does Alpha Team next; it was a quite fun puzzle game but incredibly buggy.