Okay, I changed the wording of the card so that it won't be abuseable with GP any longer.
Sadly, I had to effectively make the effect specific to the chosen target rather than applying to all of your frozen creatures... but that may be for the best.
I reduced cast cost slightly to compensate.
With acceleration this is no stronger than purify. Normally the main abuse with a creature not taking any damage is GP.
What I ask was whether acceleration counts as damage or not.
I'm not going to go into case by case specifics here.
Acceleration does indeed deal damage (see rage potion). The max HP stat is not actually lowered, the creature just loses HPs (despite the wording... which I always found confusing).
If it is agreed upon as a "physical damage" source, then this card will not stop it.
Otherwise it will.
The same will go for snipe, and all other possible exceptions.
If the damage is deemed to be "physical" e.g. the same type as attack damage from creatures, then this card will not protect against it. Otherwise it will.