Things that took me a little while to figure out:
How to un-select an ability (yes, I know shift+click is right there next to the buttons, but the first time I used it, I couldn't figure it out).
If you select a t2 or t3 ability, it doesn't remove the t1 or t2 and t1 from the shopping list. For example, clicking Total Musculature Core Revamp over to the Obtained window, it still shows I need two Musculature Boosts for my goal. Once I added one Musculature Boost and one Musculature Core Boost to the obtained list, they disappeared from the Remaining window.
Is there a way to select multiple abilities within a slot? For example, my main is working on getting to t4 in all four branches of the Alpha slot.
Is there a way to fill in the target ability intermediate steps if you already have the t2 or t3 in that step? For example, I've got Ion Total Core Judgement and Ion Judgement obtained. My target ability is Ion Core Final Judgement. I can't select Ion Total Core Judgement as my intermediate step.
The option for "Slots Share Obtained Items" might want to be on by default. I got my 7-8 characters set up in the database when I discovered what this option does. Now I have to go back and reset all of them up.
The t4 abilities are showing the need for all 4 t3 abilities in the Remaining window. Maybe a change to the interface such as Target Ability in the top box, two boxes for Desired Intermediate Abilities and then would it be possible to have the third box auto-populate? For example if you choose Ion Total Core Judgement as one of the intermediate steps the box below that would auto-populate with Ion Core Judgement (b/c you can't get to Ion Total Core or Ion Partial Core w/out Ion Core).
Ignore what I suggested earlier with the sub-folders emulating the branching trees. Once a description window is added, that will make things easier to navigate.
I'm enjoying playing with it and thank you for putting it out. Apologies if I seem critical, but I'm trying to give useful end-user feedback.