Let's say my character with Pulse wave chooses to make a close combat attack against an opposing character. The opposing character then successfully rolls for Shape Change. My character instead then opts to Pulse Wave. Can I target the opposing character? Pulse wave ignores powers, but Shape Change doesn't allow me to target him. Which overrides the other?

As I understand it, with the new rules you can no longer choose a different action if the target successfully rolls their shapechange. In your situation, if they made their shapechange roll, the only thing you could do is target a different character with the same exact power and type of attack.

Ding ding ding...we have a winner.

I thought pulse wave ignores all powers to begin with, including but not limited to shape change. So the character being targeted with pulse wave should not even be getting a chance to use their shape change as I understand it.

The first attack attempted was not Shape Change. Once the SC was made, you can't declare something else.

I see whats going on. It was a bit confusing. He mentioned his character with pulse wave was going to make a close combat attack. I thought with the new rules that pulse wave can now be used in a close combat, so I assumed thats what he was doing. I didn't see that he chose to not to use pulse wave first.

Yeah, it took me a couple of read-throughs before I figured that out, too.

At first I thought he was saying that PW used while adjacent was a close combat attack.

So, if a character use PulseWave to attack a character with Shape Change, the character using PW ignores SC?

Sort of. The precise wording is: "All game effects possessed or used by other characters with a line of fire drawn to them are ignored until the action has been resolved."
So it's not just the character using pulse wave that ignores the effects. They are ignored for all purposes.

Thank you.

I hate pulse wave cause you cant Probabilty Control ot too.

Sure you can, if your character using Probability Control is outside the range of the Pulse Wave.

You can if the piece with probability control is outside of the range of pulse wave. Preferably on elevated terrain a safe distance from the carnage.

OOOOOOOOOOOOOO really?!?!?! I hadn't read the rule that way but now I see exactly what you mean by the way the rule reads.