It is no surprise that Isaac loves Iron Man. A few months ago I bought him the ultra cool Iron Man mask now for his fourth birthday I got him the Iron Man 2 electronic repulsor blaster!
This electronic blaster accessory features motion activated lights and missiles launcher. It comes with glove and four repulsor missile accessories. The sounds it makes is pretty much exactly like in the movies. Three AAA batteries are required (seriously like most other electronic toys it should have come with batteries).
Its a cool toy but the missiles should have been in foam instead of hard plastic, which is actually a little dangerous. And here's a picture of Isaac from a few months ago at our local Toys R Us.