Right!

Jess #A:
Opens the door -> gets killed by Jess #X1. (thats the only thing Jess #A does)

Jess #X1.
This is the main Jess, which will be the same as Jess #X2 and Y, only in other timelines.
Jess #X1 rings the bell, kills Jess#A, puts her in a bag, gets an accident, and cause of the loss of her son, she have to enter the ship again to bring him back.
She enters the cruise, reads the blood on the mirror, got attacked by Viktor1. At the end she’ll enter the theater where Jess #Y shoots 3 man down.
Jess #X1 and Jess #Y confronting eachother, which will lead in #Y falling down the cruise in the water.

Now I create Jess #X2. Though this is the same person as Jess#X1, i name her different because of the 2nd timeline. Now #X1 sees #X2 aboard the cruise, and #X2 will be the one which drop the keys, read the blood (before X1 does), gets noticed in the mirror, gets Viktor2 stung and meets a fresh Jess, named #Z in the ballroom.

Now pay attention here. Cause this is where Jess #Z is created. Because a new ship entered in timeline 1; (at the place X1 and Y are confronting) this will also happen in the 2nd timeline. This is where the (for you guys) missing Jess #Z is created. Jess #Z only: flies for Jess#X2 with the gun pointed, so she turns bad and she got shot in the theater with the bag on her head, and finally she stabs sally and the other guy in one of the cabins.

Now I’ll continue Jess #X2:
Jessx2 continues her timeline by shooting at the head of Jess #Z in the theatre, and ends her timeline by the 100 sally’s. Now #X2 becomes #Y, and she sees #X2 killing #Z. (#X2 to #Y is because this is the end of a timeline). You should draw it, and you’ll see that #Y hasn’t got a past, and so she just can’t say what happened before, because she hasn’t got a past. This is with al the de-ja-vu thing. It has happend, but she can’t seem to remember it because she doesnt have a past.

My Theory ends with Jess #Y, which is created at the same time the very first boat enteres the cruise, and they see this ‘mysterious #X1. Well….#Y is looking down at #X1. #Y spies on the first group, writes the bloodwarning, dumps the bodies, shoots 3 man down in the theatre, and is finally throwing off the cruise by #X1. This is where the circle is made complete: #Y becomes #X ready to kill #A and starts all over again.

Unexplained plot points:
1)At no point does she write the FIRST note “If they board, kill them”. I see how the others got there-she’s comparing her handwriting. Would have made sense if the Jess who does decide to kill them had written 1 note and placed it there for the latter Jess to compare handwriting.

2)At no point does her necklace fall off and just hang on the grate. I see how the rest got there, but the first one (which doesn’t actually fall either) is wrapped around the grate. If this had happened at any point, she would have unwrapped it and not had to look down, causing her to lose the one around her neck. This scene should have been cut and serves no purpose (especially since it makes no sense) other than to show the viewer that this is a loop. Again, would have to be a previous Jess to fish out a necklace and wrap it around the grate for a latter Jess to find and drop her necklace, but this would serve no purpose for either.

3)If there is a bunch of dead Sally’s on deck, how come there isn’t a bunch of dead Sally’s in the theater (which is the first place we see her die)? We see her pitch the boyfriend off the deck, but at no point does she clean up the Greg/Sally mess from the theater.

4)When Jess almost shoots the other Jess in the face in the theater, this is the one and only time this happens. This creates a closed loop, which is not a loop at all. Hundreds of variations could happen each time, inevitably closing the “loop”. For a good example of an open loop-see Timecrimes, in which each scenario is exactly the same and could repeat itself forever.

Timecrimes-A+
Triangle-C for effort

Or something. My brain hurts.