I played through this mod and found it somewhat interesting. I do like a good few things about this mod, but it has flaws.
As a side note before getting into anything, do note I was playing on Master Mode.
A rather big flaw that I noticed was the pacing. There is basically no pre-hardmode content, so I'll be ignoring that here. However, when you do get to hard mode and you look at the first boss from this mod that they task you with is Galahis. In the boss checklist, it said you can fight it before the mech bosses. I did try to do this once. Just once is all it took. At first it was no big deal, simply take it slow and pay attention and it's easy. As the fight goes on, it gets faster. And just kind of stupid. One attack in particular just had me asking "why". It spawns a wall of light the goes across the screen. How high does it go? Good question, but I hope you can run or fly. Don't have wings yet? Better run. Galahis teleported in your face and then decided to shoot? Tough. This describes my experience. My main 2 issues are the wall of light, since in this game you can't just dash through it, and Galahis teleporting instantly with no warning. It has the hit box of the Lunatic Cultist, but has far more annoying attacks. You're expected to fight this dude without Chlorophyte bullets? I don't think so...
As for the next boss for this mod, Creation and Destruction. You can not fight them until after beating the Moon Lord despite the order on Boss Checklist. However, they are disappointingly easy. Get the Celestial Starboard from the Moon Lord and it's lights out for Creation and Destruction. They stood no chance seemingly effortlessly. All you have to do is equip a piercing magic/ranged weapon and you will win eventually. Simply have the Celestial Starboard as your wings with the Soaring Insignia, then hold jump, down, and left or right. Avoid anything else as needed, be it by falling or going higher. I beat them on my first try. When killing Creation first, you don't even need to put effort into dodging anything else. Literally outrun it, and keep hitting it. After this, you are allowed to craft some infinity things. I am confused as to why the gear is so much better than what it feels it should be. Beat Creation and Destruction one or 2 times each and you have enough for a good few things. Be it a godly weapon, a full set of armor, or both if you're lucky. After this, you can literally beat the Moon Lord without moving. The armor is omni-class, so it doesn't matter what you were building for up to that point. Just use whatever.
There is another note I would like to add. The Globetrotter's Sash. Why is this allowed to work on bosses? I used this against the Moon Lord and it became trivial. Literally run faster than the unicorn mount on anything. Also turn around on a dime. This doesn't seem quite right to me. Maybe that was the intention, but this just seems silly.
That's all, and hopefully you get something out of this.