The challenge with creating Sword of the Dead City was taking a formula that has been done a million times by both triple-A studios and indie developers alike and give it a coating of paint that has never been seen before.
Looking at classics like Metroid and Castlevania, I noticed that while the sense of exploration was strong, there was a lack of momentum and flow to gameplay. Those of us on the team really enjoyed games like Sonic the Hedgehog and Tony Hawk's Pro Skater, games with a strong sense of flow and timing. While I was developing the mechanics, the goal was always "how can I make this faster?". Adding things like wall climbing, dashing, sliding, and teleport gives the player tons of options for movement.
On top of speed, I wanted cinematic scope. In many games in this genre the player just spams attack on all the enemies around them. They die or explode and the player runs right past them. In our game, I wanted excessive blood, crazy finishing movies, cinematic cuts and more to get the adrenaline pumping during gameplay.
Unfortunately, like many development cycles, things didn't pan out quite as we had intended. The flow and scope of the game changed and became a more traditional side-scroller.