Impressions based on the Japanese Switch version, which is fully translated into English. The PC demo is available on Steam now and the game will come out in the west in the middle of February.

Gal*Gun Returns is the remake of the original Gal*Gun, originally launched on the X360 exclusively in Japan. This marks the series' 10th anniversary, which also coincides with Inti Creates' 25th anniversary.
So, what better way to celebrate by allowing everyone around the world experience the first installment of this paradygm-shifting series?
OK, Gal*Gun is far from being a milestone in gaming, and I would have preferred something completely new rather than a rehash of a X360 game with minimal changes. I still haven't fired up the original to make a direct comparison, but Gal*Gun Returns seems a straightforward port with nothing changed, with the exception of rendering resolution. Textures look a bit better, but Gal*Gun Double Peace (which was available on the Vita) looks better, and Gal*Gun 2 is miles ahead. Considering that all Gal*Gun games reuse the same characters, locations, and most of the mechanics, I really doubt that rebuilding OG Gal*Gun in Gal*Gun 2's engine would have been a monumental task.
Maybe doing that would have allowed developers to enable gyro controls, which worked so well in Gal*Gun 2...so yes, no gyro aiming on Switch, you're stuck with an analog stick that is good for fast, corner-to-corner movement, but not so much for precise aiming against distant targets. Hopefully a patch will solve this problem.

You take the role of the silent (but not wordless) and faceless protagonist Tenzou, which has been stuck with several love arrows by the cupid-in-training Patako, and now all girls in the school want to confess your love to you, but if you don't find your one true love by the end of the day, girls, boys, and animals will never love you again.
After answering few questions about your personality that will determine four stats (intelligence, athletics, style, and lewdness...I never understood what their purpose is in any Gal*Gun game) and selecting one of the four main girls, your journey to find true love starts.
Gal*Gun is a light gun game, so you shoot pherormones to approaching girls to pacify them. Everyone has a weak point, which pops up upon hovering the cursor on it, which works as a one-kill shot. Defeating girls will fill the Doki Doki meter, and using that on a girl will transport you to a minigame in which you have to find a weak spot, zoom onto it, and shoot it until the girl is satisfied. This will also eliminate all girls on screen and refill your health. The Doki Doki game is also used to complete a girl's profile in the gallery, and to fully complete a profile you need to Doki Doki a girl three times when she wears three different outfits (school uniform, gym clothes, swimsuit).
The cast of Gal*Gun is not composed by an endless army of randmoly generated clones, but characters with a specific appearance and voice.

Compared to other Gal*Guns, the OG game is rather barebone. Sure there's story mode, score attack, a (I think) new mode which I still have to unlock, and gallery, but the only activity going through the school is to shoot girls, there are no hidden mascots to collect or alternative paths to take. Locations only have one path, so the way you progress through, let's say, the cafeteria will always be the same in all routes. The shooting is fine, but there are no other mechanics than filling the Doki Doki meter, and there's no upgrade shop as there will be in next Gal*Guns. Frankly I feel I've seen everything the game has to offer after going through two routes, and maybe this is due to me playing the game on the X360 as well as the other games in the series.
The various bosses and other route-specific activities are cool, but other than having to be accurate and hit a specific area, they aren't all that different.

Gal*Gun Retuns comes with all DLCs available for the X360 version, but considering that Gal*Gun Double Peace is readily available in English on a number of platforms, I'd suggest to go for that instead, it's a much more varied and interesting game. If you want to stick with Gal*Gun Returns you'll have your hands full for quite some time (uhm...), as all routes have three possible endings and the gallery has a lot of material to unlock, either by playing directly or by paying with feathers collected by completing story routes and stages in score attack. Unfortunately a lot of the art present the in gallery is just at one size, you can't zoom in or out on it like many galleries in other games (not just other Gal*Guns) allowed.
One remark for the English translation: I quite enjoy it. It's not the most literal translation ever, but it fits perfectly the lighthearted nature of the game.