Defensor

Defensor would be a game for all current platforms that would be a hybrid of the hack and slash, shooter, and tower defense game genres. It would be inspired by games like Sanctum and Plants VS. Zombies, in which the goal is to keep an enemy force from reaching a certain point. This has always been one of my favorite concepts for a game, but I find its rarely executed in a way I really appreciate - I always find myself wishing that there were a tower-defense game something more like Dynasty Warriors, set on a large map with lots of different terrain elements where you could play as incredibly strong characters in over-the-top, immersive action while still bearing the larger battle in mind.

This game would have a style you might call a cross between cartoony, lightly cel-shaded, Shonen Jump-style action and a blockbuster movie. It would also not be very story-driven at all, and so wouldn't be confined to a single theme - the player would have a choice of everything from a sci-fi setting with space ships and laser blasters, to a medieval fantasy setting with longbows, horses, and castles, to a zombie apocalypse.

Gameplay
As I implied earlier, this game would include both elements of a shooter and a straight-up melee battle game. Considering that it would incorporate various types of warfare, it would also include various types of gameplay. For example, it would incorporate third person for sword and shield combat, first person for shooter combat, and so on.

Of course, though, there would be a key tactical element to battle in this game, because half the battle is keeping the larger layout in mind. Before the battle begins, both sides will have a few moments to set up defenses, such as barricades, guardian beasts, turrets, troops, and so on. However, these are simply what each side starts out with; throughout the battle, you can implement other defenses as well if your previous ones fall.

The general object of each battle in Defensor would be to capture or destroy the opposing base, not unlike your average MOBA. Depending on how well one side or the other defenses their base, a battle could end quickly or take at least a half-hour. There would be even more complexity to planning defenses considering it would have a z-axis as well - since this would be a 3D game, there would also be flying defenses, or ones elevated in the air.

Battle Themes
As I mentioned before, this game would have a massive amount of battlefield themes to appeal to as many people's tastes as possible, but there would still be a limit, as with anything else. Each theme, however, would have three preset battlefields to choose from. I'll try to include as many as I think would benefit the game and create variety. Here's the full list:

Medieval
By medieval, in this case, I mean medieval Europe - the kind of settings that remind people of knights, castles, and horses. The defenses for these battles would be more grounded, and fighting would be more melee-oriented than anything else. This would be the most grandiose type of battle, essentially. The three battlefields would be:
 * English Castle
 * French Capital
 * Spanish Palace

Fantasy
Fantasy would be similar to medieval, but it would be more like a fairy tale than real-life warfare. Magic and monsters would be involved, and the environments would be flashier and more idealistic. The three battlefields would be:
 * Forest Hollow
 * Heavenly Valley
 * Elemental Castle

Sci-Fi
Sci-Fi would be a theme focused on the classic depictions of interplanetary battle in things like comic books and space operas; it would be full of advanced weaponry and space vehicles engineered for battle. Some of the fighting would also take place in actual space, somewhat like in Star Wars Battlefront II.
 * Stratospheric Fleet
 * Uncharted Planet
 * Techno Base

Superhero
The superhero theme would be one where you could play as overpowered superhero-esque characters fighting powerful villains and their minions in different maps. These would be by far the most comic-book-ish battles, and would showcase some spectacular effects, like bubble burst effects.
 * Zombie Invasion
 * Mobster War
 * Robot Battle

Ancient Japan
The ancient Japan theme would be in the same vane as the medieval theme, but it would take place in the Eastern Hemisphere instead of the Western. You would see warriors like the samurai, shaolin, and ninjas for fan service.
 * Shogun Fortress
 * Battle-Torn Field
 * Mount Fuji