Nice game. The sounds, music and visuals (as well as the visible arcade cabinet) give it a definite retro feel and it overall seems to be pretty well thought out. I think it's clever how the laser goes through platforms but the bomb doesn't - it's easier to hit the aliens from down the bottom, but you have to be up the top to hit the UFO, forcing you to keep moving up and down the stage. 

One thing I did have a lot of issue with is the jumping mechanics. I'm not sure if I'm missing something but the jump height seems to vary a lot. It's kind of awkward how jump is Space but double jump is W - why not bind them to the same key? It's also annoying how only the double jump goes through platforms. I think the game would work better if the normal jump also went through platforms so you don't keep bonking on the low ones.