I think it was one of the first "little" games using html5 instead of flash.
I see that they've introduced a new "expert" mode, which is indeed a lot harder. I've reached level 10 so far, but I'll give it a serious try sometime.
The biggest problem for me is the language. I type a lot of English, but not being a native make me hardly write any fancy words. So my finger get "stuck" in some words that have pattern that hardly appear in my native language.
On a side note, this remind me of "The Typing of the Dead" [1], which got recently released on steam (no linux support :( )[2], and the various online clones of it [3].
I feel that games like this one are a really great way of improving the speed/accurateness of typing, while also having a good share of fun.
[1]https://en.wikipedia.org/wiki/The_Typing_of_the_Dead
[2]http://store.steampowered.com/app/246580/
[3]http://www.kongregate.com/games/ascott/typing-of-the-living-... http://www.addictinggames.com/funny-games/zombietypocalypse....