Hope the C64 gang dont throttle me here. Using a mixture of wide and single pixels. The backgrounds and cars are Iso wide pixels, while the smaller characters are 16 x 16 single pixel sprites, with the bigger sprite at 32 x 32. All special effects (shadows, smoke, sparkles etc:) are single pixels.
Edit: I've been assured by knowledgable C64 users that this mix is possible on a real C64.