I just recently got the game, and as such, this is my very first character and consequently, my very first run.
1. Did you experience the fight as too hard/too easy/just about right? Which attacks, if any, posed a problem for you?
The fight was incredibly easy. He hit me a single time with a flurry of jabs as soon as the fight started, but otherwise didn't touch me for the remainder of it. I was expecting his dash attacks and his movement to be much faster than it actually was.
2. How many attempts did it take you before you defeated him?
Normal - 1, Hard - N/A, MP - N/A.
3. What level and gear did your character have during the fight?
Level 10 - Carrot Sword, Iron Shield, Brawler Plate, Sandals, Slimy Ring, Archer's Apple.
4. What skills did you use to beat him?
Lvl 6 Blade Furry, Lvl 7 Flamethrower. (Hurray for that free skill point quest giving me silver AND bronze points!) It should be noted that I only used the Flamethower skill. Charged it up and hit him with 2 (Or was it 3?) flamethrowers and he was done.
5. Anything goes!
I thought the fight was just too slow with not enough variation. I would've liked to see some kind of dodge or defensive move from Marino, as he just kinda stood here as I shot a wall of damage into his face. Then, when he decided he wanted to attack he just kept spamming the 4-rushes-across-the-courtyard attack which required lazily moving up and down to dodge every time. Perhaps making his rush attack rapidly switch to vertical occasionally within the group of 4 would mix it up a little, if you add in some other moves as well. All in all, after dodging so many projectiles and getting used to running around a lot fighting Phaseman and GUND4M, I found this fight to lack urgency, energy, and challenge for a boss fight after the temple. I believe it would benefit from more variation in his attack patterns, a method of avoiding the player's most damaging attacks, and Marino just simply being a little faster and a little less predictable.
Edit: I reached this point in the game in about 2 hours, since somebody was wondering above. Completing this run so far has also made me feel like "Normal" is just a bit too easy. As such, all of my future testing will be on "Hard".