Glad you liked the movement! I wouldn't say you are alone with the key bindings, as it is VERY common for people to have different controls for platforming games. If I'm being honest, I actually use a different set of key bindings when I play platformers, and just changed them to the ones used here when exporting because they are considered to be more regular.
The green robots were kind of just there to give players the satisfaction of killing them. This is mainly because I couldn't perfect their AI so they are not as threatening. I think you're referring to the level with the 2 ramps, which requires you be standing near the top of the first ramp, and then run and dash once a bullet goes behind you so you can make it to the downwards ramp before the blue robot shoots again. I tended to use more blue robots to make the game feel challenging, so I understand if that was causing you trouble. Thanks for your feedback on the death timer. I also think it might be nicer to make the death animation a little shorter so you don't feel like you have to wait to get past some areas.
Glad you liked the music and the sprite work!