I am now level 27 ("The Boy" Cahill) and here it is my loadout:
= Heavy Shotgun UP2 and Photon Shotgun UP1 and Golden Friend and Impulse Minigun UP1
= Sparkly Blaster UP1 and Mercenary UP1
= Fire Orb and Chainsaw
= Napalm Cannon and Laser Bouncer UP1
= Brutal Headhunter and Photon Sniper Rifle UP1
= _0x_badcode_x0_ and Stinger UP2 and Pumpkin Thrower and Grenadier UP1 amd Mines Launcher UP1 and Ghost Lantern and Smart Bullet Bazooka UP1
UPDATE:
= Heavy Shotgun UP2 and Photon Shotgun UP1 and Golden Friend and Impulse Minigun UP1 and AK-48 (no upgrades)
= Sparkly Blaster UP1 and Mercenary UP1
= Fire Orb UP1 and Chainsaw
= Napalm Cannon and Laser Bouncer UP1
= Brutal Headhunter and Photon Sniper Rifle UP1 and Magic Bow
= _0x_badcode_x0_ and Stinger UP2 and Pumpkin Thrower and Grenadier UP1 amd Mines Launcher UP1 and Ghost Lantern and Smart Bullet Bazooka UP1 and "Bastion"
UPDATE: ("The Animal" Binneso)
= Heavy Shotgun UP2 and Photon Shotgun UP1 and Golden Friend and Impulse Minigun UP1 and AK-48 (no upgrades)
= Sparkly Blaster UP1 and Mercenary UP1
= Fire Orb UP1 and Chainsaw
= Napalm Cannon and Laser Bouncer UP1
= Brutal Headhunter and Photon Sniper Rifle UP1 and Magic Bow
= _0x_badcode_x0_ and Stinger UP2 and Pumpkin Thrower and Grenadier UP1 amd Mines Launcher UP1 and Ghost Lantern and Smart Bullet Bazooka UP1 and "Bastion" and Bass Cannon (newly bought)