Wow...
First, the technical performance is impressive
The rendering is really nice on a real Amstrad CRT. The music is really good, i would only say that it feel a little "distant" (like the digitized music in the OP intro), but this is not a big deal as it's uniform in the game. I might try to pull my stereo hi fi to see what it gives.
The game has a real Cargosoft feeling to it... Wouldn't be out of place as a (not mini) game in Orion Prime
On the game side, it's really pro. A very complete Mahjong game that, as you say in the manual, will really give a lot lot hours of gameplay.
And... I won my first game (and i don't always win at Mahjong, far from it) so it's a good sign