There are charms and weapons. Every time you buy a weapon or charm, a new one appears In its place until there are no more. After buying a weapon it will let you buy lobber or charge. The other weapons are already there. For charms, there are two starting ther, heart and smoke bomb. After buying those it will then unlock
About the coins, there is a way to get everything. There are hidden coins around the map, letting you get everything in the shop.
Inkwell isle I there’s one in
- the tutorial
- 3 from the person on the bridge
- after beating every boss, behind the razor man near the flower boss.
Inkwell isle II there’s some in
- behind the green van after beating the roller coaster boss
- talk to the juggling clown and doing his mission by parrying 4 times before hitting the ground
- behind the birdhouse following the secret path and talking to the girl
Inkwell isle III there’s only one, and it’s behind a striped cart you can find behind the shop.
The final coin is at the final boss area, behind the left row of red dice at the entrance.
The rest of the coins are in each run and gun level.