I've never understood the fascination of people with emulating ZZT in MZX, but this hardly does it -- it's basically just a hand-converted version of DEMO.ZZT and a horribly railroaded tutorial put to a slow speed with some very hackish traits. The biggest ones that come to mind are how the bombs just use MZX explosions, how the default enemies are very obviously just MZX defaults with changed graphics in some cases, especially the Shark, which dies when shot in True ZZT but does not in actual ZZT; the Ruffians are just MZX Goblins and the Lions are just MZX Spiders (funny, I always thought Ghosts would do a better job as Lions). The author did not include working centipedes in this engine, either. But... really, if you want to play ZZT games, why not play them in ZZT?