The reminder text should not state too much. The last line could be shortened to

> "Any target" now includes "target artifact or enchantment"

or

> "Any target" includes "target damageable permanent or player".

I would prefer if the definition of what damage is considered lethal is made part of the rules text rather than the reminder text - both because it leaves open other options (e. g. what if someone wants to play this with scenes) and this definition is so different from the way it is normally done.

Also you could probably should turn the sentence structure around to "Damage marked on an noncreature artifact or noncreature enchantment that is greater than that permanents converted mana cost is lethal damage."

Note that it might be better not to mention planeswalkers in that context since their damage is not marked.

Maybe you want to include the "noncreature" part into the rules text, so the reminder text can say "those permanents" or "Damage marked on such a permanent".

Note that "damage dealt" and "damage marked" are different concept and damage can be dealt to a permanent without marking damage.

Sadly, I fear this is too complex a change to fit onto a cards rule text.

Using a keyword and reminder text helps here, I guess. Kinda odd that you're choosing to make them one-shottable.

I wonder... "Artifacts and enchantments are planeswalkers with initial loyalty equal to their CMC"

Has the side effect of making them attackable directly though.

Ignoring all the rules stuff - the fact that this then only takes 1 point of damage to kill seems kinda unfortunate. Also the colours are weird, since already has plenty of ways to deal with artifacts and enchantments; why would you choose to use this to make it easier for red to deal with them?

I personally like "Noncreature artifacts and noncreature enchantments are assets in addition to their other types." ;)

I think the colors are explicitly those that can already solve the card types to keep it in-pie.