I've been looking at some maps of the game, and the style really does look surprisingly similar to Wario Land 4. For example:
http://vgmaps.com/Atlas/GBA/DrillDozer-RedDozers'TrainingCourse.png
The level there looks almost like it could fit in the Topaz Passage, at least in my opinion. Remove some of the mechanical elements and you've got a level that looks a fair bit like a Wario Land 4 toy one...
Anyone agree?
http://vgmaps.com/Atlas/GBA/DrillDozer-RedDozers'TrainingCourse.png
The level there looks almost like it could fit in the Topaz Passage, at least in my opinion. Remove some of the mechanical elements and you've got a level that looks a fair bit like a Wario Land 4 toy one...
Anyone agree?