Alternate Concept 1

High Concept
Players are athletes in a merciless, high-intensity 2v2 sport in which two teams attempt to knock the cube(ball) into their respective enemy's goals by any means necessary; Tackling, attacking the other team, moving the goal, all are allowed in the pursuit of victory. However, allies are as dangerous as enemies, because only One can emerge victorious.

Players are working together in combat and in scoring, but each one wants to be the one who scores the actual goals, hopefully resulting in some interesting states of play. This is inspired by the semi-cooperative theme of many of our primary concept's elements.

Basics
Players are split into two teams of 2-3 players each.

They attempt to pass the cube through their respective opponents' goals, while defending their own.

The Cube may be struck, shoved, or thrown while attempting to move it through the goal.

Goals may be struck, shoved, or thrown to make them easier to score into.

Other players may be struck, shoved, or thrown for attempting to reach the goal or cube.

Anything that is struck, shoved, or thrown with too much force or too many times will respawn in it's own zone roughly 3-5 seconds later.

Whichever PLAYER scores the most points in 3-5 minutes wins.

Advanced
The Cube can't be held for more than 3 seconds.

Players can't stand in enemy goal or spawn zones for more than 6-8 seconds at a time.

A player can only score on the opponent's goal.

When a goal is scored, only the player who last touched the Cube gets credit.

If a player is holding a Goal, they also get credit for any goals scored in that goal.

Physics Cube
Most play takes place through players attempting to move the large Cube to the enemy goal. The Cube will be essentially just a giant physics object, and due to its strange shape, should often bounce oddly. The Cube deals damage to anyone or anything that it strikes while moving at a high speed.

Throwing
With the press of a button, players can lift an adjacent object overhead. A second press allows the player to throw the object with a fair degree of accuracy, but a relatively low amount of power. While an enemy is held, they can attempt to squirm free. If they aren't thrown within roughly 3 seconds, they damage the player holding them and escape. A thrown object deals damage to itself when it lands, as well as anything it strikes.

Swinging
Players swing their implements in essentially the same way as in our primary concept - this is intentional, to allow integration of the game later - using knock-back to keep other players away and to move the Cube towards the goal.

Movement
Omni-directional movement with no jumping. Moving in the same direction without performing an action for ~1 second will cause the player to sprint.

Alternate Intruments
Again, in line with matching the theme of our previous concept, players can pick up new items to fight with that spawn periodically in the field. However, the only weapon groups present will be swinging weapons and throwing gloves. Different weapons will have either higher knockback or damage stats, and will have a temporary bonus effect for several seconds upon first being picked up.

Walled-Off Arenas
All the fields in which play takes place are completely walled-off, so the Cube(and players) can never go out of bounds. The default "basic" field should be relatively empty, but alternate environments should include simple pillars, bridges, or walls to allow for some variety.

Aesthetics
Like our primary concept, this would have voxel-based graphics and a simple style. An announcer would likely be used to substitute for an audience, due to the closed-off nature of the arenas.

Were this to be a full game, a single-player mode with a season roster, named teams, and much more would likely be implemented, but such additions are speculation at this point.