Lacking variety?

[DrDeath_MD]

I'm about 8 hour in and am routinely getting to the last floor but can't quite finish the boss. However, I'm starting to get a bit bored since the early floors are fairly easy and the room/enemy/gun variety is pretty limited. I have seen a few new minibosses (bat and knight) but I'm wondering if new bosses, guns, unlocks, keep dropping or if I'm starting to max out the content.

[Nick]

The game will open up further once you defeat those big bosses.