To do well in Letter Cat, you must learn to use the "tab" key to switch from one problem to the next. You must also learn to get very used to the symbols on the keyboard as well as the letters.
Your goal should be to type every symbol and letter without looking at the keyboard. If you can do that, you will do well in Letter Cat. If you can achieve a milestone score of 100, you have mastered the skills necessary to type symbols and letters as necessary for most purposes.
After you have mastered letters (complexities 1-10), complexities 12 and 15 are much more difficult. If you cannot master them, do not worry. Only very skilled typists are capable of completing worksheets accurately at those complexities. If you are trying to do these though, be careful for spaces that are not too easy to see.
some images © 2003-present www.clipart.com