Igor,
The background image is great! It really makes the website look like a fun, exciting business!
I think the background image is too big at 2.5MB, I think you could optimize it drastically & really reduce the size.
For some reason the background image is distorted. I tried using Firefox Firebug to figure out why but could only find this code in the css-compiled, master css file so I am not sure which css file the code is in but if I change it to "background-size: 100% !important;" (remove one of the "100%") the background image is not distorted anymore. Maybe one of the RT team can help you & tell you what to put in your custom css file to keep it from getting distorted.
.main-bg-blue .rt-bg2 {
background-attachment: fixed;
background-image: url("../images/backgrounds/blue/top-bg-tecture.png");
background-repeat: no-repeat !important;
background-size: 100% 100% !important;
}