There isn’t a great deal of information around about Uridium Plus. Like: whether this version has any technical enhancements (like Heavy Metal Paradroid does), or not. I have vague recollections that this version was somehow technically better, although I could be wrong. It’d be nice to know…
Maybe I should ask the game’s creator? Andrew Braybrook is on Twitter.
UPDATE: I did ask Andrew and he said this:
The Power of Twitter. Haha. 🙂
Uridium Plus does have a new arrangement of levels, each one named after a metal element, and coloured differently (which I always thought was a stroke of genius), but – in general – the gameplay is still a perfect mirror of the brilliant original.
More: Uridium on Wikipedia