amazing ability, just a few small issues
1. when you dive down it kills all of your momentum which kinda disrupts the flow of movement in an annoying manner. maybe holding down custom 1 instead of tapping could still kill the momentum for precision platforming segments
2. i feel like the dive could break fragile floors like the one in gfz2 and have an interaction whit springs like amys hammer, while shooting out of the ground could break spikes. i just think that would be neat
3. i feel like theres some floors he shouldnt be able to dig into like the grates in castle eggman or other simular looking floors that make knuckles look like he just ceases to exist while burrowed. it aint exactly an issue but i find it strange
2. it can break floors just hold jump before impact and also can power spring it's just a bit buggy at the moment also you can't even come out when an object is above while digging right now it's a bug and I have no idea why it happens
3. floor checks are awful there is really no point having to filter out certain floors I know you said it wasn't an issue but still detecting certain textures would be painful. fun fact when Knuckles is digging he does cease to exist that's how I hid him while digging