Most of this review is taken from my own comment on the thread. This is a short game you complete in under five minutes, and it was made completely by hand by one person who is clearly inexperienced. It is a completed project, but it will feel akin to a demo of a larger piece.
The art is simplistic but endearing. The game's supply of ammunition is perfectly balanced for you to be able to beat every enemy with a shotgun slug or two left over. It can be beaten with relative ease in under five minutes once you know what you are doing.
The game has only one actual "issue" with how it is built, and that's that your movement continues for a very small moment after you let go of a movement key. However, despite this being an actual problem which could have been fixed, it's also a complete non-issue. You stop moving automatically and immediately when you aim, and you can turn while aiming, so you should use this to do more precise movement the one or two times you may need it.
This delightful little game was made by one person who did everything and is clearly not a professional designer. This is a fantastic showing for someone like that, and it's very fun for what it is - a five minute spot of fun that we are getting for free.
Absolutely download it, and if you like this glimmer of the dev's potential, absolutely go support them on DLsite. The game is currently half off but even at full price, it sells for only a buck and a half. This is proof of a dev who could do pretty great work if supported.