OverKill is yet another of literally hundreds of lazy amateur 2D retro top-down shooter/brawlers infesting Steam and lowering the average quality of all video games everywhere.
It's slapped together with GameMaker Studio, so you know it's going to be garbage, but at least the developer admitted their deficiency and openly confesses to using GMS... however, if they knew that the game simply wasn't up to scratch because they had no idea what they were doing and thus used GameMaker Studio, why would they then go ahead and pay the $100 to dump this garbage on Steam, where nobody wants it (see below for the comically bad player counts and user reception).
It's a barebones, sloppy wave survival shooter where enemies come at you in large numbers from the edge of the screen so you have to shoot them... look, if you're actually looking at the Steam store for this game and saw this review, just go play Vampire Survivors like everyone else. That's the game you're looking for.
From a technical perspective, the game doesn't meet basic minimum requirements that most PC gamers expect as standard.
A choice was made to use obsolete, decades old retro pixel "art" as a substitute for contemporary PC graphics. It's unclear if this is due to lack of budget or talent, regardless, the overall visual quality of the game is extremely low as a result.
There's no option to change the resolution and no useful graphics tweaks. There's no way to ensure this is running at the native resolution of your display. There's no guarantee this game will look right on any PC as a result of this hamfisted design decision.
The game only displays in 4:3 pillarboxed aspect ratio. It's possible they developed this using an old CRT they found in a dumpster, or this game has been specifically designed for people gaming on PC's from 1995... either way, this isn't really acceptable in the modern era of PC gaming.
The controls can't be customised, which will be an annoyance for many, but it can also render the game unplayable for differently-abled gamers, or gamers using AZERTY or other international keyboard layouts.
Some of the defects in the game can be attributed to the choice of using the GameMaker Studio construction kit/toolset. This is a very poor quality toolset favoured by amateur developers as it's cheap and requires little in the way of development skill, but unfortunately has very limited capabilities. Just as you can't make a silk purse out of a sows ear, you can't make a great video game if you use a terrible engine. GameMaker Studio is most commonly used to make retro pixel shovelware and cash grabs.
A strong argument can be made that construction kits like GameMaker Studio should never be used to make games for profit, as the "developer", Kezarus has done here. These construction kits are intended to teach people some of the basic principles of game development, and to make small demos to pass around with friends. They're not intended to replace to actual work of real, professional game developers. So it's inappropriate when amateurs try to use these for profit, without any actual, real game development effort taking place. This doesn't result in products that have any real meaningful value for gamers.
These technical defects push this game below acceptable standards for any modern PC game.
The poor quality of this game is reflected by how many people spent time with it. At the time of this review, SteamDB shows the all-time peak player number was only 3 players. This is a remarkably low number, and now, the only player activity occurs once or twice a month, presumably someone loading it up to see what it is then quickly uninstalling it. Considering there's over 120 million gamers on Steam and well over 50,000 games for gamers to choose from, the overwhelming lack of interest in this low quality game is to be expected.
OverKill is relatively cheap at $1 USD, but it's not worth it. Given the defects and quality issues with the game, coupled with the unrealistic price, this is impossible to recommend. This is also competing with over 9,000 free games available on Steam, many of them far better than this paid product.
