I died to that boss 3 times but to be fair, it didn't really bother me since I'm used to that old school game design.
What pisses me off on the other hand is how broken the physics in this game are, how some commands don't execute when you need them, how the simple press on a sub menu has 1 second of lag, how the weapons feel completely off, how when your accessory comes to revive you, spends 1 second looking at you with their weapon pointed at your head before deciding to take action... and the list is long.
This is almost a kusoge level of quality.
I also remember playing games like that, and back in the day, I was a lot more tolerant of it. Having less free time to play games now though, needless repetition only works so much for me before I'd rather just move onto another title.
I finally picked it back up again last night while fixing my son's laptop. Found a good group of guys/girls online and did all three missions co-op mode. Was a bit to easy because at least 2 of them where 8 rank or higher, but was glad to get past it. Now I can do missions to get gear and go for the platinum.
If you are stuck on a mission, I highly recommend looking for help online. There may not be a ton of rooms, but I didn't have to hard of a time finding one willing to help me if I was willing to help them as well.
Tip for those who do this; You get an item in your inventory for beating any mission you had not previously defeated. To use it, you just start the mission like normal in single player, and after party select it will ask you if you want to skip the mission and use your item to do it. The mission will then load, and one it starts it will immediately end saying you beat it and assign you a 1 star win for it. If you want to dot hat last set of 3 missions this way, just talk to the angry boss girl in the courtyard outside your room to accept the first mission, but then don't start it, go back to your cell, and talk to your accessory to chose cooperative. Once you host/find a game to join, you talk to boss girl in that session and chose the first mission. If you complete it, you'll have the next mission automatically to try next.