Nice! Gotta love asteroids, never gets old hah. Nice to see someone using GameMaker, underrated engine imo.
Nice choice for the sprites, like to the way they look, took me a moment to realise that the asteroids were 3d, but honestly I actually quite like the look, a similar look for the ship might be nice, though I do like the look of the ship as well.
I think some nice additions would be: SFX/Music, and an effect for the asteroids getting hit to help confirm that you've hit them.
I do think that technically having mouse movement AND mouse click is technically two inputs, however this is something you could easily solve maybe by either having the ship spin constantly and press the space bar to shoot or have the ship shoot constantly and press the space bar to spin.
Either way, fun game!