Feels pretty good to move around, and I like the camera motion.
Something about the jump feels a bit off, but maybe it's just me. If I had to guess, it could be that the upward motion is too slow (time/speed in reaching apex), but changing the jump sliders doesn't really solve the issue. It just feels inconsistent. Also, the character queues one jump in advance if you press the key. I'm assuming that's intentional, but the second jump height is either less or more than the first, even if I only quick-tap for the first, which doesn't come off as intuitive.
What I don't like is how the player slides off slopes. It should be on/off. Either he's stationary, or sliding off at a constant speed to indicate it's too steep, not in between.
What's the secret text about?
Overall, really cool. Looking forward to seeing more updates!