Add an animated background. (we can use gif. Like... Why not ?)

Well, we can add in db how many times user did answer correctly. Simple as it is

Window with questions should parse the questions first. Then input them in Text Boxes.

User inputs the answer to the question in the spec text box (should be marked "Your answer here"). If the user input (without any quotes and etc) == the answer (answer will be in small letters. Without any void info ) - Make an animation of the correct answer, else make an animation of the lock. After that text\new window should pop up saying was it right or wrong.

In the Welcome screen need to add Functionality to the register button

Add functionality to check the user in DB. If he exists - transfer him into questions

Add login functionality to the welcome screen

Damn. We can parse some kitty or other shit with questions like "wanna have more ?". Smth like this. If the user responds by saying "yes", we just transfer him on the page with questions "how many times and etc".

Pop up a small window with suggestion what to do next

В Sort и Filter надо добавить exception-Ы и проверку, чтобы дата была датой, а не хер знает чем

добавить дату и сделать графики через javafx (опцион)
progress bar в javafx (как стата)

ФИЛЬТРАЦИЯ
Больше не нужно

On correct login show questions in a new window
This one is hard.

Adding function of Finishing the program if the user inputs no, or clicks the spec button during the game

Ask user in the beginning, how many times does he want to try each question and how many questions he wanna have.