What a cute game, everything about this is cute. Starting with the file size, over opening a tiny little window, over the sound effects used. And then there is the walking animation which looks like a little penguin waddeling. :D
It was a short little enjoyable experience. The shooting mechanic was quite interesting, the direction of the bullet seems to be affected by the current velocity the character has? Didn’t quite figure it out, but that left some place for skill expression for sure, which could be extended in further levels. I think the colors work great and everything is clear and nicely readable, good job on that.
The biggest annoyance with the movement is, that you get stuck on terrain often when jumping, because you always have to press the forward key after you are already over the height, else it get’s canceled. That doesn’t feel particularly well, and is not really necessary to preserve the retro feeling in my opinion. Also having jump on X and Z is kinda meh, i would like to use my thumb for something, especially a key that you need alot. I kept confusing both of them just because they are so close together.
Also the sounds seem to glitch out on the little green tanks, it still plays after they get destroyed.