Reached the final boss and I only unlocked 5 weapons that are not the starting 3 main or repeater I just reached the final boos (Nightmare) and have not unlocked a lot of weapons.
Primary weapons:
Coach gun
Shotgun
Hunting rifle
Sniper rifle
Eye of the storm
Devastator

Secondary:
Repeater 
Defiler
Hive cannon

Am I missing something from this game ? I am pretty sure that I cleared all of the areas that I can remember. Getting bored of my combo of sniper + defiler,