PGTD consists of three modes- Recruit, General, and Veteran. The modes scale in difficulty, recruit being the easiest and veteran being the hardest. Veteran mode is a test of strength and skill combining everything used in both Recruit and General against you. It requires you to work with your teammates (if you're playing with teammates). With the modifiers, you can add a whole different level of difficulty to the game, although your modifiers cap at 235%. The most common way to do 235 is with the modifiers: Stronger Enemies, Impossible, and Regeneration. These modifiers make even something like 235% recruit into a tough challenge, throwing new types of enemies at you like Kamikaze, who is quick and stuns nearby towers upon death.The final challenge and hardest difficulty of PGTD would quite obviously be 235% Veteran. Buffing enemy hp by quite a margin, for example the Conqueror, the final boss gets its hp buffed to 126 thousand health. And while already a difficult and daunting task with others, like all things it becomes even harder alone.