Very cool game! I enjoyed this one a lot! 31 is my best score!
I think it could be better to have real name every time instead of having a base name with some extra random letters at the end. We could start with names with 3 letters, and every "X" heroes, it increase by 1 (so it's not necessary to up the speed).
This is just a suggestion, I really enjoy your game, Congratulations! :)