Why it's built this way
Platformers ask you to commit to a jump and be right. Climbing games ask you to maneuver: find the holds, budget your strength, rest when you can, and only commit when the move is safe. Crux puts both on the same wall.
The first pitch is the whole game in miniature: a slot with an ice pillar on one side, which you can only bounce off, and a jug wall on the other, which you can rest on. Both reach the same ledge.
Holding grip on rock lets you cling and climb, slowly, on a stamina bar that only refills on the ground, on rest ledges, or on the good holds (jugs). Anchors are checkpoints you place yourself; you carry three per pitch, placing one takes a second of standing still, and any fall or hazard returns you to the last one. Rock chutes, wind bands, crumbling holds and ice all have a timing to them, and a gripping climber is safe from wind while an airborne one is not.
The slow way. Climb on the holds, wait out the rockfall on a jug, anchor before every crux, arrive at the top having never fallen.
The fast way. Wall-jumps and dashes cost no stamina at all, and a hop off the rock covers two metres in a blink for the price of a few seconds of climbing. A confident climber chains up a chimney in seconds and skips most of the holds; a fall costs more without anchors, and that is the whole trade.