a couple more thoughts, ctrl could also be used as a crouch key as well as making your hitbox smaller(dunno if it already does this) for crouch jumping
also the flying feels a lot more natural in the test level than it does in the first level and i think the reason for this is because of the ample frame of reference, it's hard to judge your velocity unless you're near an island. maybe air-speedlines that swish past you to show the direction you're moving in could help. having a skybox with some color gradient would help a too, but i think the main thing is just having more.. things floating around. those big grate type shapes in the test level are great for a visual reference in midair, interesting shapes that are clear at different angles/distances are what you want more of i think.