In some ways, this game is easier to play than the SNES version.
The gameplay is quite smooth and character movement feels marginally faster. (Though it may be the method of playing the game, rather than the game, itself). The character could move around at a good speed, attack, use spells, etc. The menu system takes full advantage of the keyboard, allowing for near-instant access to what you want.
The monsters in-game had a 'little' bit of variety in terms of attacks. Some of them launch themselves at you and some throw magic around to defend themselves, for instance.
My personal nits about the SNES' version of the 'hit box' for your character were already severe, but this version allows for some slightly easier combat. To fight, you hold your sword button down, and CHAAAARRRRGE at the enemy, much like Ys. Fortunately, the enemies do not deliver one-hit killing blows and your shield is useful at pushing them away, too, so this greatly improves your odds of survival at lower levels. Still, boss battles are not easy, so it is best to be careful. At least you can save your game right before facing one.
Now for the unusual similarities to Ys.
- Item and Inventory system is 'literally' a perfect match for Ys. The equipment system used 5 swords, shields, armor and rings, EXACTLY like Ys. The item system was a list of stuff, including a limited number of items you could carry only one of each at any time, EXACTLY like Ys. There was trim around the inventory and items pages... maybe not exactly like Ys, but sure felt familiar. Combat is like Ys, too, where you charge at your opponents.
And for some differences.
- Attack button. You have to hold it down before running into enemies
- Magic system. Ys' magic system was based on a mix of attack and support magic. Lagoon allows you to combine staves and you currently equipped sword cast different kinds of spells. However, where in Ys, magic is necessary for boss fights and parts of the quest, you can get through Lagoon without magic if you want to. It is rather useless in boss fights, unless you equip rings.
- Rings. In Ys, rings are useless against bosses and very useful on the field. In Lagoon you can equip them anytime, even during boss fights, but they cost a LOT of magic to operate, so it pushes you into doing what you have to do and getting it done ASAP.