Sorry if this sounds harsh, but : the buttons and the boxes having the exact same shape is confusing, the red laser destroying the boxes but not damaging the player is not intuitive, having limited ammos only allow the player to get softlock (good things there are checkpoints) and the whole game itself is pretty slow and not very fun.
The mechanics all works well and the art is good dont get me wrong. You did a good job in only three days, but I can't even compliment the idea behind this game because I have no idea what you were going for. How does this fit the theme "echoes" ? Answering "Completely" doesn't really help you.