For what it's worth Putmalk I would say it is better to have that element of exploration, and having unforeseen rewards better still. You just have to make sure that there is no good or bad ending, just alternate endings each as 'good' as each other. As Cranky Old Man says you don't want players feeling pissed off cause they didn't get the ending they wanted
As long as you make it clear to the player that exploration is important, there is no need to discern between correct and incorrect paths, and if you really do manage to pull off having multiple paths of progression as well as multiple ending, that would be a far more interesting design decision than having one path with optional extras in side-rooms. It'll just take a lot more work.
Aside from that, it's a very good looking map mate nice work. It definitely looks like something I don't want to play, and that's a compliment