I remember Hewson Consultants from a few years back with their Nightflight flight simulator, and it appears that they haven't been idle in the meantime. Uridium is a fast-action arcade shoot-'em-up, and pretty impressive it is too.
The action takes place above the surface of some large structure, possibly a large enemy spaceship, which scrolls horizontally against a background of fixed stars. The background scrolling is quite simply the smoothest I've ever seen on a BBC Micro, and up to the standard of arcade machines.
The enemy ships are also made more 'real' by using the two shades of blue and black to give an impression of shading; they, too, move very smoothly: Your task is to shoot down weaving and looping enemy ships, destroy ground installations and, finally, set down on a landing strip before moving onto the next wave.
Even though it took me a long time to load the game from cassette, I was left with a good impression - the graphics impressed me that much. The controls were a little awkward in their action; the positioning is user-definable but the forward/backward response was strangely weighted, though quite playable. Apart from that, the game is technically excellent.
The various stages of the game are associated with metals: Zinc, Lead, Copper and so on. Uridium is presumably the highest level, but I didn't get anywhere near that far into the game! I tired of it eventually, but given an arcade trackball I could have played for hours.