* Springs no longer need MF_SOLID to function. (I tried to add a special Sonic...

* Springs no longer need MF_SOLID to function. (I tried to add a special Sonic 1-3 style "springs are solid from the side" thing with native support, but it turns out that requires too many hacks for an optional extra feature not used in the campaign, so No.)
* Springs no longer send you flying relative to the slope whilst you're on a slope. (I tried fixing this before, but this is a much more solid fix.)