> It admittedly gets a bit more difficult when these hacks and quirks are part of what create the unique feel of your game engine.
An example of this in the Quake 3 engine (and now permanent behavior in the CS series) is air strafing. It's a glitch in how Quake 3 handles motion vectors. But it's now also enshrined behavior, complete with entire game modes in CS built around it (KZ & surf maps). If you went and made an entirely new engine, or even just used something off the shelf like Unity or Unreal, you'd have to add that bug back. It's core to the gameplay now.
To add to the list of 'bugs that are now features', in SF2 'combos' were a bug, they were not intended to be part of gameplay. Their inclusion is arguably the basis of the 1v1 fighter genre.
To add on, players like this feel enough that this behaviour is very convincingly replicated by Riot in Valorant, which is a CS-like game on Unreal engine.
An example of this in the Quake 3 engine (and now permanent behavior in the CS series) is air strafing. It's a glitch in how Quake 3 handles motion vectors. But it's now also enshrined behavior, complete with entire game modes in CS built around it (KZ & surf maps). If you went and made an entirely new engine, or even just used something off the shelf like Unity or Unreal, you'd have to add that bug back. It's core to the gameplay now.