Linux Gaming

I'm not sure what you mean by tactical shooter but flathub has a subcategory for shooters in the games category. While half of them are source ports of Doom, Quake and some other games, there are a few games I've looked into that seem interesting. So far I've only played Empty Clip and that's a pretty good top down shooter with rpg elements but games like Red Eclipse and Tremulous look pretty interesting as well.