Ten ways for me to add challenge to the Carrier Artang game

 I've done it. I've created my first game for my new business. It's still in its rough stage, but I've been able to create an outline that I think will serve me well over the next few weeks as I complete my test of the new system. The game works, but there is no real challenge. And that's what I want to address today. What could I add to the game to make it more challenging? Please add your own suggestions in the comments, if you wish. 

• Random levels of damage on the carrier, both incidental and deliberate.
• Submarines are a constant threat, as well as sea mines/torpedoes.
• Perishable planes and pilots, as well as fluctuating morale.
• Firm time limits.
• Limited ammo or fuel for planes and/or carrier, as well as randomized rearmament. 
• Lowered attack strength or defense strength.
• Iron-clad defense (increased armor). 
• One defense = 2 attack. 
• AEWACS and ECCCM.
• Player starts off damaged and needs a repair. 
• (bonus) Learn how to create a simple machine learning program that adapts to the selections of the player. 
• (bonus) Nuke strategy.

This is the list so far. Ideally, I should be looking to implement each of these ideas into the final product. It will take a while, but I think that I can get this done. If not now, then when I transfer to Unity later this year. I'm really excited about that. So, let me know your thoughts.