I got my Epic item on a mission on death (Dense Fog), so yes its the hard way but just play the game and you will get it.
Rare items have an star (bronce color), item max is 50, you get alot of them on "Hero"
Epic items have an star but bigger and are (gold color), item max level is 70, got mine in Chapter 2 part 1 Dense Fog so the more you play the more epic items you get
Legendary items have an half moon (gold color), item max is 90 (got it by spending 1 "Happy Card Free Passes")...my guess will be you get them on insane.