If you're new to the megaman series or want to try a megaman game, the zero/zx series is the one you'd go with. Unlike his predecessors, Zero is not limited to his ranged attacks and has the z-saber for melee. The availability of both ranged and close-ranged attacks makes this series easier to play, at least in my perspective.
As you might've seen on other reviews, this port does not allow you to freely arrange button locations. Instead, you decide which of the assigned button do which function. However, it's not bad as it seems.
My assignments for the zero series is: keyboard type 2, in-game assignments: j- main weapon; u-sub weapon; space- jump; o- dash; j- attack with main weapon, u- attack with sub weapon
ZX is about the same as zero, except you have the new transform and overdrive buttons, which I assigned to i and 8 respectively
Difficulty wise, these series aren't too bad if you don't decide to challenge yourself, especially with the save assist function in this collection. Even a player who isn't very skilled like me could unlock the ex-skills with some practice.

If you're new to the megaman series or want to try a megaman game, the zero/zx series is the one you'd go with. Unlike his predecessors, Zero is not limited to his ranged attacks and has the z-saber for melee. The availability of both ranged and close-ranged attacks makes this series easier to play, at least in my perspective. As you might've seen on other reviews, this port does not allow you to freely arrange button locations. Instead, you decide which of the assigned button do which function. However, it's not bad as it seems. My assignments for the zero series is: keyboard type 2, in-game assignments: j- main weapon; u-sub weapon; space- jump; o- dash; j- attack with main weapon, u- attack with sub weapon ZX is about the same as zero, except you have the new transform and overdrive buttons, which I assigned to i and 8 respectively Difficulty wise, these series aren't too bad if you don't decide to challenge yourself, especially with the save assist function in this collection. Even a player who isn't very skilled like me could unlock the ex-skills with some practice.