A dreaded suggestion regarding Immortality.

[Lanidrak]

I agree with that purify should be extended to 1) also target creatures and 2) effect more than just poison... I guess that will be another topic for another day - but in brief: Adrenaline, Infection (poison), Aflatoxin (poison) and Momentum should all be removed by Purify.

Things which affect the statistics of a creature will not be removed by purify - but I'm unsure as to whether or not to include Antimatter in this.

Anyways, Xinef - Immortality will be very useful. Especially if you know what your opponent has. For example, if your opponent has an Elite Otyugh in play, with Quintessence. You could play your Lava Destroyer and then Immortalise it to let it grow. Also, you could use Precognition (another spell) to see whether or not your opponent has any means of damage in his hand, or whether or not he has anything that could target an Immortal.

As for the shield' effects making Ethereality to go off temporarily, I like it, but it will be very difficult to code or implement.

[Xinef]

Anyways, Xinef - Immortality will be very useful. Especially if you know what your opponent has. For example, if your opponent has an Elite Otyugh in play, with Quintessence. You could play your Lava Destroyer and then Immortalise it to let it grow. Also, you could use Precognition (another spell) to see whether or not your opponent has any means of damage in his hand, or whether or not he has anything that could target an Immortal.

Ok, so when do you know what your opponent has before the duel, so that you can decide whether to take immortality or not? And your opponent does not know what you have in your deck, so that he cannot prepare to remove your immortality?

I guess when fighting AI3 and AI5 immortality might be useful, because the most common creature control is probably poison, plagues, lightnings, lightning storms, rain of fire, eagle eyes and fire/ice bolts. No lobo in AI3, rarely seen in AI5... mind flayers also rare... fallen elves and rewinds a bit more common, but AI does not know how to use them properly.
I am not sure about false gods... it might be good against some, like morte and fire queen... so maybe people fighting only gods they can beat would use immortality, but I guess rainbows aiming to beat every god would use quints...
In random PvP though I guess damage based creature control is much less common than devouring, eternities, mutations and such... and you still do knot know what your opponent has before the duel.
I don't know tournaments, so maybe you are referring to those?

And if you mean taking immortality just in case your opponent does not have a way to counter it, and you simply do not use it if you know he can counter it, then wouldn't you rather take quint? It seems ethereality would be harder to counter and more reliable. Unless you are playing a mono/duo deck with , but prefer not to take ... or immortality would cost 2 or less and quintessence 8 or so, but otherwise rainbow decks would prefer quint, and people would prefer splashing to take quint rather than splashing to take immortality.

[BluePriest]

As for the shield' effects making Ethereality to go off temporarily, I like it, but it will be very difficult to code or implement.

Not really, because all youd have to do is say something like

if (etherality == true && congeal == true)
{
targetable = true;
}
else
if(etherality == true)
{
targetable = false
}

Should be really simple to do in all honesty. You just focus on the effect itself, and not how you get the effect since the only way you can get the effect is through a shield on immortal creatures.