A sticker is out in a storm. Draw shields with your finger to keep it dry while rain, hail, bouncing balls, splitting blobs, lightning and falling anvils come down in waves that keep getting harder.
Your first line starts the storm. Draw shields anywhere, as fast as your ink refills.
Each wave brings something new: hail that chips ink, bouncers, splitters, lightning, and boss waves full of anvils.
Pick an upgrade between waves, spend coins on permanent ones, and collect stickers from boss waves.