MAKAI TOUSHI SAGA / Squaresoft / Wonderswan Color
This is the first game in the long-running SaGa series, but it's better known in the west as Final Fantasy Legend (from that early 90s period where Square was hellbent on attaching "Final Fantasy" to every franchise they localized somehow.)
This remake is almost like a Game Boy Color remake of FF Legend, since the Wonderswan hardware is fairly modest. They didn't go for much in the way of changes but doing up the graphics a little bit and adding color. Apparently a few engine tweaks and wrinkles from later SaGa games were brought in, but I've never played any of those so I can't comment.
What I can tell you is that this first SaGa game plays as if you took the engine of the first Final Fantasy for the NES, but swapped out its battle engine for that of Dragon Warrior 3. But it also mixes in some ideas from western RPGs, and does a few completely original things of its own. It's like Square just said to the director, "Take the fundamental FF engine but just kinda toss in any other ideas you like, mix it up and see what comes out of the oven."
You start out in a town with a huge tower, and the goal is just to eventually scale it. You'll have to unlock it first, though, by roaming the neary countryside to find a set of holy equipment. From there you scale the tower, which periodically opens up into a variety of other lands.
You start out by creating your own party of up to four, and SaGa gives you a pretty impressive breadth of class types for an old Gameboy game. You've got your standard human male and female, then a mutant male and female, then there's just an absolute heap of monsters. The way characters level is more quirky than the usual RPG. There's no real "EXP", per se. Humans use equipment normally, but can only raise their stats by buying fairly expensive potions. Mutants can use a smaller range of equipment, and randomly may get stat gains after any given battle; however, their four "special ability" slots are also bestowed randomly, and can randomly come and go after any given battle as well. Monsters have to eat meat ripped from the bones of your slain enemies to power up; however, only the meat of monsters more powerful than they are will advance them, and any monster can change into any other given type of monster. To progress in the game, monsters will almost constantly have to be shifting types to get by.
The game is a bit too grindy and reliant on randomness for my tastes, but I do acknowledge that it's a very solid RPG with a lot of content and a surprising amount of depth for something that originated on the Gameboy. The remake doesn't do anything wild but is a decent aesthetic upgrade. It's also one of only two 100% completed fan translations that I know of for the Wonderswan (the other being Dicing Knight.)
* Tower Reversed translation
* Gameplay Video