A nice idea, but with a very limited implementation. The core gameplay is reasonably fun, but it gets boring awfully quickly. The art is basic, which is fine, but it would be nice if there was more variety in the enemies and background tiles.

Also, it lacks "juice". A way to improve this would be to add some blood splatters and perhaps persistent bodies, and maybe some screen-shake when you fire your turret.

Another little nit-pick I would give is that the score font is really not suitable. If you are going to have a pixel-art style game, the font should be pixel-art too, otherwise it just does not look right.

I realize that these may seem like very small things, but making a good game requires a lot of small tweaks. All these little things add up to make the game feel a lot more fun to play.

As a side note, I think this would be a really good game for mobile devices. The one-button input seems ideal.

Anyways, hope these criticisms are useful to you. Good luck with future game deving!

An interesting (although not original) concept, executed extremely poorly. It just isn't fun to play.

For starters, the mechanics aren't particularly tight, and your character runs really slowly, making the necessary retracing of steps an absolute chore. The difficulty is stupidly hard in the worst kind of way. It's just trial and error, with no skill, which is not at all fun. Throw on top of that the fact that you then have to retrace your steps, and it's just salt in the wound.

The graphics are also pretty damn bad. I wouldn't necessarily mind that, but there is some inexcusable stuff. Text is often unaligned, for example. That's just laziness.

The music is okay I guess. That is probably the only redeeming factor. But this is a game, so that ain't enough.