I had too much free time.
Version 1.4 changes:
* Party cannon firing angle improved
* Rarity fires more gems and the delay between each one is reduced
* Rarity's aftercast delay is reduced
* Twilight's magic beams travel faster
* minor graphical improvements
Version 1.3 changes:
* Changeling blasted counter now shown on result screen
* "Play again?" and "Return to main menu" don't appear instantly so you won't missclick them
* Milliseconds now show the correct 3 digits
Version 1.2 changes:
* Pinkie Pie's aftercast delay reduced
* Pinkie Pie now fires more projectiles
* Rarity's attacks moved a bit to the right
* The magic bar now has a white background
* Changelings don't fly too low now
* Added a "Changelings blasted" counter
Version 1.1 changes:
* fixed bug: when you use a character before the game is over the game runs insanely fast after restarting it
* fixed bug: keyboard not working without clicking on the game window
* added a "Return to main menu" button
Why are the ponies 8-bit?
> Because I'm lazy to make animated vectors for the Mane 6.
Why aren't all other graphics 8-bit too?
> I couldn't find 8-bit Changelings and the background didn't look very good in 8-bit style.
Please report any bugs or put change requests in the comments.
Feel free to use this game on your personal website if you want to.
I hope you haven't forgotten to use the secret cheat code

That's pretty good considering how much I fail at games like these XD