If you search for a game with special characters (like # or ~) it shows a 404-error page. If you search for a game with a + in it, it ignores the + in the search. I haven't found other special characters which become ignored yet.
It's probably like that because of the site still being new, they havnt worked everything out yet. I would send them an email telling about your problem.
For now you can just search for the other words in the title, or words that may have been tagged relating to it. Then the game may still appear under the search.