The new Iceman has this power:

GLACIAL WALL:#Iceman can use Barrier. When he does, make a close combat attack targeting each opposing character adjacent to a marker just placed. Each hit character is given an action token and is dealt 1 damage for each action token it now has.

Here's the thing. Does this power allow him to attack each character adjacent to every one of the markers, or does it allow for only characters next to a single marker? "Adjacent to a marker just placed" is a bit vague and can allow for both scenarios depending on its interpretation.

I was kind of wondering the same thing, if an opposing character is next to more than one barrier marker can you attack that character more than one time?

The way it looks like it reads to me is that you place one marker and then make your attacks if possible, then place your next marker and make attacks and so on until all 4 markers are placed.

I could very well be very wrong about this but that is how it reads for me.

The way I understand it is that Iceman uses Barrier, places up to 4 markers as described by the rules for barrier, and then makes an attack roll that targets any opposing characters now adjacent to the placed markers. Basically the same situation as a character making a ranged attack against multiple targets, but instead of splitting the damage between them you assign the tokens and then deal the damage as defined in the "Glacial Wall" power.

it looks like all markers

Also, because there is a period after making the attack, and not a semi-colon the wording is a bit ambiguous. Do you get your normal damage in addition to the token and damage?

You would make an attack against any opposing character that's now adjacent to a barrier token. Not one attack for every barrier token they're adjacent to. It's like Poison Ivy and her smoke cloud but with ice and you have to roll =D

Yay for vaguely worded special powers!

No, It would specify it the same way i does on other cards. It would say something like Deal 2 damage in addition to your regular damage.

EDIT: Polaris offers a good example of this

MAGNETIC CRUSH: When Polaris uses Telekinesis and places an opposing character, after actions resolve, she deals damage to that character equal to her damage value minus 1.

Granted, it's just my impression, but I understand it like this:

Iceman's player declares he uses a Barrier.

1a. He places the 1st marker.
1b. He makes a Quake-like attack targeting all characters adjacent to that marker.
1c. Each hit character gets a token (unless they already had 2 of course, since no character can have more than 2 action tokens).
1d. Each hit character is dealt damage equal to the number of tokens they now have (so either 1 or 2 if they had 1 before being hit - I understand that even if they got hit while having 2 tokens and they got no additional tokens, they are now dealt 2 damage, since the Power doesn't specify that they only take damage for the token(s) received from Iceman, just that they need to be hit).

2a. He places the 2nd marker.
2b. He makes a Quake-like attack targeting all characters adjacent to that marker including the characters that were already attacked after placing the 1st marker (possibly also the character(s) that were already targeted and hit with the previous attack).
2c. Each hit character is assign a token (unless they already had 2).
2d. See 1d.

3a. He places the 3rd marker.
3b-d. See 1b-d.

4a. He places the 4th marker.
4b-d. See 1b-d.

I would think you would place all the barrier tokens then make the attack. All of the tokens are intended as a single barrier such as a wall or a bolder. While you might be able to destroy a part of the bolder or wall the overall object is still a single unified piece to begin with.

This is the way I read it as well.

The bolded part is what is making me think that you place one marker at a time and make attacks after each is placed.

It says a marker, not all markers, so I was under the impression that you place all 4, choose one or the markers and make an attack only against all opposing characters next to that marker.

It'd be great to get an official ruling though.

This is incorrect. The Rulebook states:

You must completely resolve one action before you begin the next action. Resolving an action includes resolving any free actions or game effects that action allows, followed by applying action tokens and then pushing damage to each character that received a second action token during that action.

So when he uses barrier he has to resolve barrier. He can't stop in the middle of one action to resolve a separate action. You would use barrier, placing the markers. Barrier resolves. Now, the secondary effect triggers that when he uses barrier he can make a close combat attack targeting each opposing character adjacent to a marker. This is triggered by using barrier. Barrier which reads specifically:

Give this character a power action; place up to 4 blocking terrain markers in distinct, adjacent squares of clear terrain that are all within this character’s range (minimum range value 4). At least one of the terrain markers must be within line of fire when it is placed. The terrain markers remain until the beginning of your next turn.

This means when you use barrier, if you stop at one, you have chosen to put down one blocking terrain marker. (it's up to four not four) You have to, according to the rule book, resolve barrier before using the second effect of his special power to make an attack against adjacent characters. The attacks are not a mechanic of barrier they are given to Ice Man from a special power trigger after he uses barrier.