Ys 4 for the SNES was handed off to Tonkin House to port from the Turbo CD, just like Ys 3 was; they did a very capable job on 3, but definitely less so here. Whoever did the boss chiptunes renditions of the music from #3 apparently was still employed, and turns in another very good score that's really the highlight of the game. Other than that, though, it's all downhill.
After experimenting with a side-scrolling style in Ys 3, Mask of the Sun reverts back to the overhead-view "bump into the enemies" combat style of the first two games. If you're not familiar, basically you have to walk into an enemy from any angle *except* for head-on to damage them; if you hit them head-on they damage you instead. This was originally done because the first Ys games came out on the MSX in 1987 and presumably the programmers couldn't do any better then; coming back to it in 1993 with this release is just strange. Even more so that they keep the "four cardinal directions only" style, not allowing either you or the enemies to move diagonally, leading to combat turning into a weird dance around each other most of the time.
Though it's clunky, combat is actually easy here as you grind up extremely quickly for some reason. It's almost shockingly easy to gain levels and stash up a pile of loot to buy the latest and greatest weapons in this one. More of a pain in the ass is the fact that every environment in the game is some annoying maze with a lot of long dead-end branches (some of the towns included.) And while the enemies rarely pose a physical threat, there's some really obnoxious areas where they inflict status effects that you only have limited ability to heal, such as early on where you have to dodge through some forest of poisonous snails that infinitely (and unpredictably) spawn all around you constantly. The difficulty also rockets through the roof at boss battles; there's only a handful of them, but they often have at least one attack that kills you instantly regardless of your equipment and level, and do that thing where you have to dodge around endlessly before they give you a 2 or 3 second opening to do a little damage, then its right back to the Dodging Forevar.
Ys 4's music lends it some panache, but honestly the graphics and gameplay are both super-dated, and the plot is just boring and leans on standard anime cliche. There's a full translation patch to English by Aeon Genesis if you want to give it a spin anyway, though.