It crashes when it starts the first wave 🙃.

Debugger:

___________________________________________
############################################################################################
FATAL ERROR in Vertex Shader compilation
ShaderName: shd_flash

D3DXCompile failed - result

at gml_Object_obj_enemy_single_Draw_0
############################################################################################
--------------------------------------------------------------------------------------------
stack frame is
gml_Object_obj_enemy_single_Draw_0 (line -1)

This feels really fun to play, and the mechanic is neat. I like how when an enemy is on one HP, it's optimal to catch one shot, dodge the rest, and snipe them. Maybe add in some 1-health enemies to take advantage of that?

My only real complaint is restarting. Why do I have to move my hand over to the enter key? It's the sort of game that would really benefit from a really from being able to jump back in straight away.

Clever idea! The graphics are good and the gameplay is nice.

My only problem is the smoothing of the shield rotation, for an action oriented game, it would have been better to have the shield follow the mouse/joystick movement instantly.

Anyway, good job overall!

I liked this one, definitely challenging but rather well-made and executed. Having no direct control over when you shoot is an interesting choice.

The aesthetics of the game are pretty nice as well.

A few notes:
1. I do wish there was actually a bit more of a delay on when you start shooting after absorbing bullets (either that, or faster aiming), as your first shots almost always completely miss because you can't rotate your shield around quickly enough. 

2. I think your recommendation of using a gamepad is actually kinda misleading, as I find it far harder to pull off the precise aim needed with a joystick than with a mouse.

3. Some visual indicator for when your shots are about to fire would also be nice (ex. the shooting portal visibly charging up), but it's certainly playable without it.