The design decision to make Akuto: Showdown go from 3D to 2.5D in Akuto Zero was to implement a much-requested feature from players: physics movement.
When I say physics-movement, I am not talking controllable ragdoll bodies like Gang Beasts, I am talking about allowing players to jump of ledges and climb on top of blocks. Players in Akuto: Showdown wanted this feature, especially in levels like Acme Corporation where there were locations with higher grounds. But I designed the game where all characters use NavMesh Agents. If you don’t know, NavMesh Agents are components in Unity that allow you to create characters (usually AI) and allow them to walk around in a world while avoiding obstacles and other players. So why did I give it to human-controlled players?
The reason I gave them to human-controlled players as well was to make use of another feature of NavMesh Agents, which is that they ensure the character always stayed grounded. Some of the original levels, like Pier level, had no borders and a fall that would lead to instant death. Without NavMesh Agents, players would have spent more time in these levels focusing on movement instead of combat.
Now, I could have possibly designed levels differently by ensuring that players could never fall of them. This would have fixed the movement issues, but having physics-based movement in 3D Akuto would have led to combat issues. In Akuto: Showdown, players can aim in 360 degrees from the position they are standing, but they cannot aim vertically (up and down). As you can imagine, this would have led to a bad core gameplay loop. Players would be able to keep jumping up and down to avoid being killed and even jump on top of players that are on the ground without the player at the bottom being able to do anything to kill them.
I could have added more buttons to the game to allow vertical shooting, but that would have compromised my vision of keeping the game simple.
Since there are only four movement directions in Akuto Zero’s 2.5D gameplay, I was able to design physics-based movement without compromising on the game’s vision. And if players want to jump on other players, they should expect a bullet coming up to them from the grounded player.