Fun, but too many performance issues.
This is an enjoyable enough non-scrolling "auto shooter" type of game, with a base defence mechanic. It's nothing too ambitious, and doesn't have a huge amount of variety, but can be fun for the first couple of hours.
The English localization lacks polish at least, with many text strings not fitting in boxes (at least in docket mode) haven't tried handheld mode, but the real issue comes from performance. I'm not sure of the game engine, but it feels like one of those badly optimized Unity games on Switch. The first tell is whenever the upgrade pop-up appears, it fails to animate properly, instead pausing the game for a second then appearing, this happens every time. The problems come more severe once you unlock the 3rd stage, which gives you an 'endless' mode. By the time you reach around level 40 in that stage the game isn't playable, you've got 1 frame every 2-3 seconds, sometimes with 30 second pauses, and severe audio-break-up; the game engine simply isn't optimized at all for the number of things on screen. All you can really do at that point is wait and allow yourself to lose, which when the game is running that badly can take half an hour.
Maybe it fares better if played on a Switch 2, but I've not been able to test. It would have made more sense for this to have been released on one of the more powerful consoles rather than the Switch.
In conclusion, it's enjoyable for a while, but the game breaking performance issues you quickly encounter mean there's little point in investing any time getting deeper into the game beyond those first few hours.