I really like the animations! The recoil looks pretty realistic. I’d have to say the spark from the first gun after shooting looks pretty unrealistic, but apart from that I like it!
I honestly need to say that looks good, but there’s some parts that you should add for this FPS game that you’re making.
Starting with the first thing, the animation. The animation in the video looks nice, however, needs to have a reload animation for the gun when there’s no ammo. Not just this but also a head moving (when you zoom your camera) animation and a shake head animation when you fire.
Another thing is the rig. When I saw you grabbing the tool (gun), I noticed that the left arm got dislocated, which means that the rig is R6. I prefer that you should try putting as R15, just like Arsenal.
Now the gun, I unfortunately can’t give feedback since this is not your creation and yes a free model, but what I can say to you is that you should try making your own guns in Blender.
But in general, looks awesome and hope you can improve a lot and make it super duper cooler for your FPS game project.