I am pretty sure there are no restrictions on usage and the source code is included, so you can customize it. There is nothing in the MUY IMPORTANTE section, it is just a reminder to press the back button in the browser to come back to the site, and an warning that there would be 2 pop-up windows when you click to download.
[Update]
Just read the "readme.txt" file (leame.txt) and it says is Open Source, so, no restrictions.
[/Update]
"The five senses obstruct or deform the apprehension of reality."
Jorge L. Borges?
"Premature optimization is the root of all evil in programming."
Donald Knuth, repeating C. A. R. Hoare
"To die for a religion is easier than to live it absolutely"
Jorge L. Borges
