Yes, but there are already enough challenges on the site that use exactly the same encryption…nothing new is being tested here.
It is my opinion that this site was created to offer new and innovative challenges. After all anyone can go to another site and solve simple substitution ciphers!
I could understand the need for one or two of these (for absolute beginners that have no experience) but why is there any need for more of the same?
We are aware of this dilemma and of the fact that there are much more level-1-challenges than according ones for the other levels which are only variants of the same core cryptographic problem. There are two main reasons for this: First, we want to offer new users enough training material to improve themselves. Secondly, most of these challenges have been handed in by users, who have already invested a remarkable amount of time and effort, and created a well-thought challenge with a nice and appealing story. I think it would be unfair to reject only because it is too easy for advanced users and because the core crypto problem is already covered in another challenge. We try to make sure that each new challenge even in level 1 has at least some new flavor or variant before reaching the actual crypto problem.
We are always looking for new and innovative challenges for each of the four levels and you are more than welcome to hand in your own challenges or to suggest topics/encryption methods so that our team can come up with challenges for this area of cryptography.