Quote Originally Posted by p(3.14)
Btw it was the tutorials on your website that started me with game programming, so I guess it's another "thank you"
That is always nice to read

The alt-tab crash happens when I go back to the game. A popup appears saying the canvas does not allow drawing.
Btw, I also noticed here that the main window name says Form1. It isn't a really big deal, since your game runs fullscreen anyway, but I think it wont hurt changing it in something more appropriate.

Bullet time sounds like a bad plan. Players dont know about it and will conclude that your game is buggy.

As for checking for a hit. I think there's a better way to deal with that.
Some years ago I made a small game called Pop the Balloon. (] then doPerformHit()).
It's superfast and very accurate.
Only downside is that you'll need to figure out an easy way to load all sprites (including animations) into arrays.