Writing this immediately after finishing BOOMCAKED mode - holy shit, the Nitromare Demon is a colossal difficulty spike. I have to damn-nigh strain my eyes to properly navigate the spew of piss-coloured micro-bullets it spews out, and I'm pretty sure I got past that purely through luck.
(Also, the medal for dying as JC was shockingly easy, considering he dies in one hit)
Overall, I'd say gameplay's pretty solid - bullets feel hard to focus on (they've all got this soft edge to them, except the really small ones which double up across my screen), but that's probably just my laptop monitor being kinda shite.