Mega Man & Bass is definitely not beginner friendly, but it honestly gets better with each playthrough if. Especially if you notice certain things about boss patterns, but I do admit e-tanks would've been nice, and some parts could be balanced better. But if you ask me, it's become the best entry period for it's levels, weapons, upgrades and 2 playable characters.
How I'd rank the classic series.
B>6>4>11>PU>8>V>5>7>9>>IV>III>3>2>I>>1>>>10>>>II