I created Re:Battlegrounds as a way to create one of the first Re:Zero based fighting games on Roblox. I mainly took mechanics found in Jujutsu Shenanigans and other battlegrounds games to create a simple but working Re:Zero battlegrounds game.
By the end of development, I have created two character movesets, which was enough for me once I stopped development.
Like many battlegrounds games, I started by programming the basic combat of the game. At first, these were just M1s (five punches), front/side dashing, and blocking. I had tried to make a new mechanic, grabbing, which was meant to counter blocking, but it was impractical and not fun to use. When I first made these mechanics, it was quite barebones and barely worked, with many optimizations needed so that it functioned smoothly.
When I first made M1s, I used a animation-event based system where hitboxes spawned once an animation marker was triggered, making it frame accurate. In general, this approach is better than using task.wait() or other methods due to its accuracy in timing.
Dashing, however, was a mess to figure out how to code. Due to Roblox's inconsistent way of applying physics, it was difficult figuring out which method was best for a battlegrounds game. If you don't know, there are three main methods of applying a velocity to a part/model: LinearVelocity, BodyVelocity, or directly calling Part:ApplyLinearVelocity().
But the main reason I decided to stop development was simply because the game lacked creativity. The whole game was basically a lacking copy of Jujutsu Shenanigans, down to the mechanics and the UI.
If you want to see the current game and it's code, the following links are provided: