To quote a certain message i saw more often than intended: "It's a hard game". I'm not sure yet when i'm going to use the trophies the last two bosses dropped. But different to other games with RPG elements in this game the satisfaction stems from the actual act of defeating the boss and not the gosu loot he droppped

Given that i can see why the indomitable is so frustrating to some. If you don't have the right idea (there are several character choices, but not too many) you won't even get close to getting him down. If you have the right idea you just need some tries and you will get a run, where you don't even have to be too carefull to avoid mistakes. He/she is quite either/or boss giving you little feeling of progress until you actually kill him.
I agree with everyone (or most) that there certainly is a need for more easy/medium content, but that's obviously a matter of time and not because the developers want us to suffer. Just as the need for more difficult content

Currently i also missed the number of challenges the freeware had, where you had to beat dungeons with classes you didn't like. But again this is probably a matter of not being implemented yet.
Great game so far. Given the Beta Status i have encountered very little bugs and i'm very excited for those slow content developing weeks

Regards,
Julian