Its kind of worked in a lot of ways, and copies will set you back the price of a couple of booster packs, which is more than can be said for most Un-set cards
The central mechanic of having to discard cards to improve the odds of passing a test (cards you put in your deck because you loved them
such as Dark Magician the Knight of Dragon Magic, Neos Armed, Synchronized Assault and many more
Using Shadramon was probably not the best idea against her
Dont be afraid to use existing Magic cards as a resource to find inspiration or make sure your cards are realistic (unless you want to design joke cards like 10,000 Emrakuls
Its most promising line is Meltan, since it can generate Steel Energy on its own, while Melmetal can protect itself from damage and deal a consistent 120 each turn