and you can also fly up and down by mouselooking.
Being someone who remembers it as if I liked Sonic The Hedgehog "Reboot", I feel like 10 seconds is way too long a float when compared to Sonic The Hedgehog "Reboot"'s 2-ish seconds. And while the "boost" ability is a nice addition, I feel like having 2 seconds of it is also too much, making him too overpowered in comparison with (2.1's) Sonic/Tails/Knuckles. Maybe a 5-second float and a 1-second boost would be more balanced? I'd like you to try. You can always revert it if it feels too short.On another note, here is a concept for Silver's ability, and, well, feedback on it would be pretty much appreciated.
I can't think of any other way that could be used, personally speaking.
The thing with using buttons rather than mouselook is that it makes the ability even more complicated to use, and way less precise for that matter, since you can actually choose the angle YOU want using the mouse, rather than having to deal with a fixed angle while going up and down.
On the topic of the ascending/descending controls, how about making Silver's boosting control sort like Brak Eggman's missiles, only faster? That is, make Silver move forward at a fixed speed while boosting, and let the player angle his flight upward by holding Forward and angle it downward by holding Back. That way, Silver's boosting controls would be intuitive for anyone who's flown a Brak Eggman missile before, and they wouldn't require players to use the camera controls or the custom buttons.