Xtra Spicy Enforcer 27
The plane level is surprisingly brutal on Xtra Spicy. My first attempt -well, after the attempt where I hurled myself into the abyss with an unintended dodge, thanks Enforcer- ended in failure pretty much entirely because I spent the time to retrieve the BONUS letter that's right there when you start the mission. In the time it took me to get back to the pilots and clear everything out, they were already 80% dead, and it only took barely screwing up from there for them to be finished off.
So yeah, rush to the cockpit first thing if you don't want to fail the mission.
Once that's done and the area is largely cleared out, it's possible to range out and get stuff anyway, and indeed I managed to get all the BONUS letters in the end. I missed out on the researchable item, but only because I've been continuing to lag on jump upgrades. I made a point of prioritizing it after this as a result, which is probably waaaay too late but oh well.
No weird surprises with nasty boss monsters, at least.
See you next mission.