Playing through Halo Infinite recently has reminded me of what I personally enjoyed about the original Halo: Combat Evolved game. The snappy and satisfying gun fighting, enemies who react to the player actions and the unpredicitability of those NPC reactions. I'm seeing a lot of that in the current Halo iteration with Infinite and while I was watching a shoot out between the marines and Banished it got me thinking of another old game from way back in the day. A custom made map for Starcraft called Aeon of Strife. In that mode two NPCs armies fought it out while the players took on the roles of powerful heroes who worked on shifting the tide of the tide of the fight. It made me think how Halo already has all the pieces in place to design a game mode like this with minimal effort as the fundamental assets are already created. (In corporate speak: It would be cheap to make an entirely new product which might draw in new market share.)
The Fundamentals
Designed to be played in 30 to 50 minute scenarios this would have a similar structure to a MOBA game in that it starts fresh each game. You'll one two opposing forces on opposite sides of a map. The differences being that most of the map is controlled by the NPC force and a number of objectives and points are scattered across the map for the players to approach. These objectives shouldn't just be boxes to check off a list though, taking them should change the flow of the game. Whether taking one downgrades enemy weapons, increases time between enemy waves, limits their air support, you get extra units in your own wave of NPC, or a number of other effects that would change the flow of the fight.
As MOBAs have shown us, only a single map would be needed for this game mode, so long as that map had enough dynamic elements. Then learning the map and its different variations becomes part of the gameplay itself.
Reaching a designated goal then ends the game. (See more details on said goal below in 'How to Keep it Fresh') If the NPCs overrun the player base, they lose.
How to Keep it Fresh
Now the danger of having an NPC opposing force is the risk of stagnation and repetition. To avert this, this mode would lean on dynamic elements that are determined at the start of the match. Perhaps your opposing NPC commander prefers air support, in that case shuttles with enemy units would be more common. Or they prefer overwhelming force, so the waves of enemies spawned are larger. Or they like to send out stealth units to disable player assets. There's also the advantage that the Halo NPCs already offered varied behaviors. You could also add a dynamic system that tracks the playstyle of the players (Does the player always pick a certain path, fortifications could appear there. Do they prefer to hit objectives and not fight enemies? Now those objectives are better guarded.) The NPC forces will also make some of their own 'moves', actions they take that will require player intervention or which could result in defeat if not addressed properly. (Whether that's a larger offensive, or aerial assault, etc.) To make these 'moves' fun for gameplay they should be able to be foreseen, whether that's announcing them at the beginning of the match and the players can weaken them through certain actions, or perhaps by hitting certain objectives to reveal what these moves will be.
Along with dynamics elements to the battlefield. It would be good to add in-game progression and meta-game progression. In game progression would be taking objectives that allow you to call in NPC reinforcements or unlock vehicles as certain goals are achieved. Meta-game progression would be small perks you can take into the game with you. (As this wouldn't be a PvP oriented game you could play faster and looser with balance, since over balancing can often be to the detriment of fun.) You could also implement in-game leveling, players gain more shields, faster reload times, more ammo or grenade capacity and other RPG elements (I would just recommend that actual damage not be linked to this leveling or the game has the danger of enemies becoming spongy, which is the opposite of what makes Halo gunplay satisfying.) These would reset each match to again reinforce that fast paced atmosphere and sense of progression each match.
This game could be tweaked to be played solo or with a group, it would just be a matter of balancing the number of enemies that spawn and how often the NPCs make their own moves. The goal for the players can also change, whether it's to execute an NPC to trigger victory, destroy a base core, bring bombs to their base, etc. These different win conditions can again keep things fresh.
Additional Room for Gameplay - Asymmetrical PvP
While not intended to be the core feature of the game, PvP could be implemented by allowing a player to take on a 'commander' role for the NPC side. However, rather than setting their win condition to be 'Wipe out the enemy base' I would recommend their win condition be different from the players. Set some sort of metrics to measure play fun/engagement, including even a player measure of "How much fun did you have?" and set that as their goal. This way the commander is aiming to create the most fun for the players they're up against rather than finding the most efficient way to end the match. So rather, they're finding the most efficient way to create fun. Rather than directly control units they would have the ability to direct NPC reinforcements, enemy spawns and other tools to allow indirect interaction with the players. (This could even include just flavor options such as having a hologram come down and taunt the players/act as a distraction.) The idea being that fun for one group shouldn't mean less fun for the others. As this is asymmetrical gameplay it makes sense to have asymmetrical goals.
Summary
What is proposed above is a game play product that plays to the core gameplay strengths of Halo. That's the snappy gunplay, the reactive enemies and unexpected AI, and the large scale conflicts with multiple forces. With all the assets created and enemy AI already largely in place this would be a relatively easy and cheap project to undertake. This game would likely need to have scaled back graphics to accommodate more units in action and also more complicated behaviors on a range of different computer rigs, but the trade of top of the line graphics for gameplay is one which indie games have shown us often pays off.
Note: I know this post and idea aren't going to go anywhere. This was just a fun thought experiment as I've been enjoying the Halo gameplay and also enjoyed those increasingly rare horde-mode shooters so I thought I'd jot down the idea. No need to point out this will never get made, or that anything which isn't traditional Halo is a waste of time. Think of this as a fun creative writing exercise!
