Not a guide really. More of a heads up.DO NOT
click start new campaign when going for this achievement. It resets all of your ego. Making it extremely difficult to complete.
This happened to me
Now I've finished my Insane playthrough (collecting the ego again as I went) I'll try and share some things which helped me get through it.
Never use beer/steroids/holoduke unless you come to a section that you just cannot pass without it.
If you get a shrink ray, don't drop it unless you really have to, they can make certain things (flying miniboss guys/octabrains) so much easier.
A lot of the sections when you are on a rail are very difficult, (I'm looking at you Crash Course), here you need to learn the pattern of the enemies. When facing the seemingly endless fighters whilst stuck on a turret, you have to abuse the aim-assist function by 'pumping' the left trigger. It constantly will snap to the enemy you are aiming near. Be careful not to overheat though! (Video added below)
In some places, dying after reaching a checkpoint part way through a big battle can reset the weapon drops. When you first find the shrink ray on the roof and where you have to collect the barrels to move the crane down are two places where this helped me.
Conserve pipe bombs for fighting octabrains.
The shotgun and railgun are vital to getting past some points in the game, these were my most used weapons, although I carried the gold pistol through too on this playthrough.
Fighting the Queen was tough, staying on the left and bouncing pipe bombs off of the pad above, unload RPG on her, kill small creature and repeat until the octabrains start spawning. Switch to the right and abuse the pipe bomb ammo to kill the octabrains and a few more mags of RPG ammo (5 shots spawn in the far right corner as well). (Video added below)
Battlelord Dam fight - For his first health bar just run to the other end of the bridge and unload on him from distance, easy. His second health bar is more difficult, he rushes you now. Stay behind the truck in the back right corner of the highway. Then use your pipebombs and keep grabbing more from the ammo point behind you (this depends on getting the boss to stand in the right area), or jump and peek your head over the truck and shoot him with the RPG. You'll need to sprint across the other side of the dam between minigun attacks if you need ammo for this though, You can pretty much ignore the other enemies unless they start attacking you, if you leave them alone, they generally leave you alone. (Video added below)
When you fight the octabrains in the bay with the turret, (the first time you see the Octaking. Grab the railgun and fall back, then kill them from range. They will stop spawning eventually. When on the turret against Octaking, I kept getting killed by him, if you're going to die, jump off of the turret and run forward and right, you can hide behind the pipe to replenish health.
When I was fighting the Octaking I had a holoduke, I used it straight away and hammered him to take his health down enough to move on to the next stage. Dodging the wave attacks is easy in comparison to the first part. Be careful though, he often leads his shots. (A beer spawns in the corner by the hut). When you know that he is going into that final stage (pulling you towards him) make sure you have reloaded. As soon as his life bar BEGINS to fill back up start shooting him. Unload on him and reload as quick as possible. I've uploaded a video below, this shows how it's done with no holo duke or shrink ray. Having both of these items carried over from Fork Stop makes it even easier.
When you have to go down the ladder and rotate the platform and you get rushed by octabrains, I climbed back up the ladder and killed them from in the doorway at the end of the corridor, thank you rail gun.
Final Boss. A helpful tactic to ensure you have a ton off ammo is to keep killing the pig cops who spawn in the first stage and leave the ammo to build up on the floor. This only helps to get through the second phase more easily. Third phase, the most difficult part. Try and avoid fighting with the spawning enemies unless you have to. Focus your fire on the boss and start strafing. If you strafe to the left of the ammo box first, unloading on the boss, then strafe back to the box to get more ammo. Then strafe to the other side of the box this time, and back again to get ammo. Repeat this and you should be able to kill him in no time, just don't stay in the same area for too long. (Video added below)
If anyone is stuck on a particular part then just leave a comment/PM me. maybe we can make this the FAQ the loading screen tells us to go to
Edit: Video added for Queen Bitch, Crash Course Turret, Battlelord Dam Fight, Octaking and the Final Boss on Insane