The game is very appealing, both graphically and in terms of soundtrack. The tutorial is also well done.
The gameplay is super hard on the default settings, but it can be cheseed by changing the hotkeys, as you noticed. Maybe increasing the reload time of the cannons when pressing a key on cooldown could solve the problem without removing the customization of the keys.
But in just 10 days you did a great job! Seeing old CRT TVs is always fascinating :)