Hey yo this is an awesome game. I've played the first one and this is a preety good one too, it reminded me of titanfall 2 in some parts of the game due the plot in some points.

I have some ideas that might interest you for the grand finale.

1.- Multiple endings depending on the max weight of the protag. This can trigger an alternative ending (optional) where she became the new enemy of the galaxy by letting the parasites numb her mind and taking control of her becoming the new "queen deity".

2.- Once finishing the game a new game plus slot with a few new details to be unlocked (such as a new difficulty , weight or extras), by the way the time travel possibility in chapter 7 open a lot of possibilities like: Go back in time and recruit the other Queenie bosses characters, this leading to trigger a little plus event against the final boss. Things like that....

3.- When Sasha joins the group (if she does) give 2 or 3 options (recruit her normaly, fuse with her giving a new image and maybe abilities)

4.- Maybe this will be implemented in the final version if it is just ignore this part ... A weight tracker might be good, to know the max level of each part (I have seen so far.. bust: 140, ball: 80, belly: 100 (not sure if this are the max or if there is a final one were the player needs to farm a lot of exp in those areas))     

5.- A secret event if Freya succeds giving "life" to all planets, the life goodess rewards her with a new ability to fight against the other goodesees in a 1 vs 1 battle (the ability to make her gigantic for the battle) meanwhile the other members are supports in the ship giving Freya attk buffs and negative ones to the enemy. This could lead to Freya eating the other goodesess, have "fun" with them or just beat them to get the items.

This are my ideas so far, I hope you like any of them or inspire ideas for future game projects or even maybe a DLC..... Best regards and thanks for a great game.