Origin mode is harder than Hard mode since you are taking more damage now and the bosses has even more health but again its not that hard if complete the hard mode this should be easy for with exception of Intestinal Distress boss but i updated my guide with glitch to beat him easily but still the level itself can be annoying a bit but in overall its not that bad.
Here is a full walkthrough of the game incase you are stuck on certain spots and that will happen most likely.
Update: Intestinal Distress boss can be a pain but i found a glitch to take him out easily, go to the far left screen and stay there the boss will jump to left of you and will damage you one time and he will get stuck behind the rocks from your same position aim on top left and start shooting toward him you will hear his voice when he is taking damage keep doing that and claim your easy win.
Update 2: Once you reach the second part of Buttville just lose all your lifes and the achievement will pop, A nice glitch will save you the troubles of the last level.