Great game here needs attention in how it's presented. The TDC download is an exact duplicate of the Micro value disk one, both are PAL - ONLY and I see red garbage at the bottom of title screen. Cassette version is the best and also PAL - ONLY. All versions are XL/XE only probably requiring more than 52k RAM.
"Mouse Quest" is the EXACT same game but not as good for these reasons: the Amiga version was named Mouse Trap not Mouse Quest, MQ was updated to no longer crash in NTSC but game element (s) such as music continue playing at different speeds PAL v NTSC so the update isn't really complete, and the person updating removed Brian Jobling name for their own? as if...
I think all should get a good look at this game mainly the cassette version in PAL emulation on a XL/XE. The Engine conveys the power that the entire screen can animate whatever you like! But I'm sure it has its limits. Makes you wonder why or how games having this much virtuosity didn't appear sooner on the Atari 800, here's my take. Game engine probably learns lessons discovered on 16-bit platforms like Amiga and BOBs (bit block objects) and probably also strip down the Atari OS for max speed resulting in an XL/XE hardware requirement.
NTSC mode only ever locks up when a BOB is scrolled on or off screen at top or bottom. My emulator only pauses not locks and simply switching to PAL then has the effect of unpause. Too simple a fix to go and remove BJ name for one's own. Anyway, the other Amiga game "Global War (Spitting Image)" draws with the same engine, pauses when missiles and bombers scroll off the top and bottom. This kind of Game Engine for Atari 800 became very popular among the Eastern Europe revival of software following the fall of communism and the Berlin wall. There are many examples on atarimania coming from Poland and Czech in the early 1990s.