Appeal and exporting

A few classic principles add life. Squash & stretch: a bouncing ball flattens on impact and stretches as it moves fast, which sells weight and energy (keep the volume roughly constant). Anticipation: a small wind-up before a big action (a crouch before a jump) tells the player what is about to happen and makes it hit harder.

Exporting a sprite sheet

Games play animations from a sprite sheet: all frames laid out in a grid in one image. Export with evenly-sized frame cells and a transparent background, then tell your engine the frame size and count. As with static pixel art, use nearest-neighbor filtering so frames stay crisp.