Me? Yes, only one Ys Strategy though the biggest problem I had with said game was the controls.

No, but there are many aspects of the Ys games that I dislike. For example:

* In some Ys games, you can't access the menu during boss fights. I find this to be rather arbitrary.
* I don't like the fact that one level matters more than it should. This actually even forces minimum levels (I believe Ys 2 requires getting close to the level cap or else you can't damage the last two bosses). It also means that, if you do things out of order (possible in 6 and Felghana), part of the game will become absurdly easy, even on Nightmare mode.
* I don't like the heavy use of electric guitars and similar instruments in the music.

For specific game issues:

* Ys 1 has that one bat boss that I consider to be one of the worst boss designs I've ever experienced. (If you've played this game, you know why.)

* In Ys 1, in the later part of the game, there's no more levels to gain (so XP is pointless), and there are no more shops (so money is also pointless).

* Ys Origin, if you play as the third character on Nightmare mode (which I have not done), has one part early on that does not look fun (having to wait for Boost to refill, and being severely punished if you messed up). I don't like the fact that an entire aspect of the game (getting a currency for some upgrades) is basically eliminated on Nightmare mode. (I consider that sort of thing to be poor difficulty design.)

* Ys 6: Ark of Naphistim, if you are playing a version other than the English PC version, has way too much backtracking; you have to go through a certain cave *way* too many times during the course of the game.

* Ys 6 and Oath in Felghana both have at least one permanent missable, which I consider to be poor game design.

* How are you supposed to beat Ys 6's secret boss without cheats (level 60 cheat on PS2 version), Boss Rush mode, or Catastrophe mode (which is exclusive to the English PC version)?

Very late to this but Nightmare is what is name suggest. It is for player skills and not character skills or the abuse of abilities. The attacks are usually time baseds and the enemy has pattern, you have to perfectly memorize those to be able to survive long enough to deliver enough damage. This is all and it is true for all Ys games. In a story playthrough you can easily overlevel enemies because as it was said even a single level matter. There is a minimum level cap for resistance and piercing, above a certain level you become more resistant against attacks below your level and your damage do extra damage to armor (easier to break through boss defenses to deliver actual damage). Ys was never meant to be played like that, it is just for fun anyway.

If Nightmare is supposed to be about player skills rather than character skills, then why does one level matter so much? I don't mind having to learn the attack patterns of bosses (particularly if I've chosen to play on a higher difficulty level), but what I do mind is having to reach a certain level to have even a small chance of winning in a reasonable amount of time, and I also mind the possibility of breaking the game too much by over-leveling. (As I mentioned, in Oath in Felghana, by doing things a bit out of order, I can easily get enough XP to trivialize two of the bosses.)

That one part in Ys Origin that I mentioned, which is not a boss fight (contrary to what some people think, boss fights are *not* the entirety of the game), is bad game design because of how much waiting around you have to do. You aren't dodging enemy attacks during that time (in fact, it's actually better to come in at low health, because then boost refills faster), you are just waiting until you can continue with that task. It's a shame because there's a later part of the game, namely that one place with the nasty music where you're constantly losing health and have to use Boost and the thunder attack that heals you to stay alive in that area. (That brings up another point; I don't like the fact that the healing effect is disabled during boss fights (well, except for a couple cases that the developers overlooked).)

Also, the upgrades you get from the currency, while nice, are not even close to game-breaking, and I think that making them effectively unavailable on Nightmare mode is a lazy way of increasing difficulty by taking options away from the player.

I guess I just don't like the rules changing in arbitrary ways when there's a boss, and I found that one non-boss part to be poor game design.

The opposite way, the minimum possible level is what Nightmare enforce. It is a challenge for a reason. If you not know the pattern inside out you will lose healt faster than you can damage the boss. If you ever played caravan shooters or hardcore bullet hell games (Touhou and Crimzon Clover is not hardcore) then this is the same. It is about surviving rather than being able to effectively kill the boss. The boss can kill you fast, you can kill the boss slow. You have to conserv your healt very long in order to kill it. As for regular areas Nightmare not really chance anything as there is hitstun and such. The only noticeable difference will be later when your passive abilities will be below of regular enemies because of the lack of upgrades. This is not for regular playthrough, if you have no fun playing like that then play casually like me.

Felghana and Napishtim, but I have to say the this second one is a total sh**ty game. Frustrating and not funny, what a videogame should be. Felghana lasted me a few days circa, and once its finished it doesn't "give" you nothing, because you have to start a new game. Its not worth my time.

I didn't said I and II plus, because they only have a stupid combat system.

I have only played up to Felghana through the Story path listed on Digitalemelas, and so fair I've liked every single game. I did try out the DS port of Ys 1 and 2, though, and frankly it was really hard to look at. I would've preferred it if they stuck with 2D graphics.