The Chant

You have way more than 12 upgrades so this achievement doesn't make you have to beat the whole dlc without dying. Personally I didnt upgrade much until I got to upgrade my swarm ability (green prism)/4th one out of 6. Then I backtracked and upgraded from the ones I passed earlier in the blue/yellow/orange sections. The shortcuts to access the guy stuck in walls should already be unlocked so you can easily access them because they are shortly after you exit the caves.
ps. SWARM IS OP

You have way more than 12 upgrades so this achievement doesn't make you have to beat the whole dlc without dying. Personally I didnt upgrade much until I got to upgrade my swarm ability (green prism)/4th one out of 6. Then I backtracked and upgraded from the ones I passed earlier in the blue/yellow/orange sections. The shortcuts to access the guy stuck in walls should already be unlocked so you can easily access them because they are shortly after you exit the caves.
ps. SWARM IS OP

What both the game itself and the other guide fail to explain is that after collecting a prism ability from the acolyte in each color section, you can talk to Monroe back at the nexus to get a SECOND upgrade for each acolyte. (Or at least, this is what I gather from reading guides on Steam.) If you're like me and get all the way through the final boss still waiting for some explanation of how you get the other 6 upgrades....if you hit "continue" from the menu you'll be dropped back into the nexus but all of your stuff will have reset. Talk to Monroe for 6 upgrades, then you have to go back through all of the color areas (hopefully you opened the shortcuts) and re-collect the 6 upgrades from the acolytes. Enemies will have reset as well, so you do have to be careful to not die while making this run. (Extra tip: on revisiting the Indigo area, you can run straight past the two giant frog bosses to get to the acolyte and then the warp point back to Nexus.)