I've unlocked roughly half the roster, getting clears on Drizzle is pretty easy, but I haven't cleared higher difficulties (I haven't played Monsoon at all yet, I want to unlock at least every survivor before doing that). Also, unlocking alternate abilities is done with little trial things which is WAY easier than how it goes in RoR2. Unlocking Commando's entire alternate slate took about ten minutes vs. hours in RoR2.
So yeah, it's good. I don't think I'll drop the same 300 hours into it as I did RoR2, but that's 99% of videogames, it's still really good.