In Crow Country, you'll be able to get a variety of weapons during your journey. You'll also be able to upgrade those weapons by finding some of the game's secrets. One of the weapons that you can upgrade is the Shotgun, giving it a handy Laser Sight much like the Handgun. Here's how to upgrade your Shotgun in Crow Country.
How To Upgrade Shotgun
Once you've earned the Silver Key you can head into the Gift Shop from the main Crow Country area. This is where you'll find your Shotgun upgrade. You can solve a different puzzle to get the Magnum from the cash register in here, but you won't need to solve it in order to upgrade the shotgun.
If this is your first time in the Gift Shop or if you didn't kill off all of the monsters in here before, there will be some creatures in your way. You can take them out with your gun or with some Grenades before you weave around the Gift Shop shelves and behind the front counter, where the cash register sits. Just be careful, since it's pretty saturated with monsters inside.
Next to the cash register, there's a closed shelving unit up against the wall. You can approach it in order for a "little mushroom boy" to pop out from inside of it and offer you a reward: an upgrade to your Shotgun! To accept it, just tell him you want what he's offering, and you'll immediately get the Shotgun upgrade. You won't need to go into your inventory or otherwise equip it. Accepting the upgrade from the Mushroom will give you an automatic laser sight upgrade to your Shotgun.