[ti]demon[/ti]Which is harder?

That is a pretty hard question actually. Lets look at the facts.

The 1st mini wave in Conical Drepression is the hardest part of either of the levels. Heck, its even harder than most of Bloodbath. What also must be considered, as stated above, is that Conical Depression is not terribly long and it also gets gradially easier. The very end of Conical Depression is pretty much just to see if you are still awake. Keep in mind that most of the level after the 1st wave is still very hard/ insane demon difficulty.

Now Phobos is XL, which means one must endure the whole insanity of 2+ minutes. Many parts are not too bad and can be related with some hard/ very hard demons but there are some stupidly difficult parts scattered throughout (like iBlade's part) that can trip up even the best of players.

Unless you play on mobile where the 1st wave in Conical Depression is an impossible piece of crap, Phobos is slightly harder imo, however, I do realize it makes sense if you may think Conical Depression is harder. There isn't really a right or wrong answer.