It's probably not that the gameplay code is tied to hardware speed (as that would probably result in the game running too fast, like what apparently happens with some old PC/DOS games), but rather that the exact gameplay experience is designed around the hardware having a very specific strength so that the (inevitable) slowdowns will trigger at the same exact points. In the case of ports, that hardware strength has to be accurately emulated/simulated or it results in an inaccurate port.Shepardus wrote:The fact that that's even an issue is concerning (albeit not surprising) because it implies that the gameplay code is tied to the hardware speed. It's far from impossible to keep the two decoupled (for specific examples, notice that MAME runs at the same speed on any system assuming the system meets the base requirements to run it at 100% speed, or just play any online multiplayer game). If you target both PS4 and Xbox One, or even just PS4 and PS4 Pro, you're already going to have to deal with that, albeit to a lesser extent.
The actual problem is that they probably should not have exceeded what their hardware could handle at full speed; if the game always ran at 60 FPS, nobody would complain about slowdown inaccuracy because it wouldn't have slowed down originally. Or if they absolutely wanted to have that many bullets while still wanting accurate ports, they could have just had the game go half-speed at a certain bullet and/or object amount that the hardware could just barely handle at full speed, so that the slowdown wouldn't be hardware-reliant.