An absolute must have for any VR owners. Now let me explain.
TL;DR: H3VR is a singleplayer gun simulator which includes over 250 different types of guns, and it is updated frequently to feature more guns and weapons. There are several maps to try out and even a couple types of game modes to play.

H3VR is a great game, it was the main reason I got my Vive headset, it's full of content and things to try out. The physics in the game are splendid as well, very realistic but there can be a few bugs at times but they can be quite hilarious to see. One of many things you can do is bounce shells off your shotgun and manage to load it into your gun, or line up mags and knock them over like dominos.
The game features a lot of guns and "toys" to play with, well over 250 guns now, ranging from pistols, to rocket launchers. They all feature the little details that each gun has, for an example. Most guns need to be ♥♥♥♥♥♥, and have the safety switched off, or have the firing mode changed.
There are a huge variety of weapons to choose to play with, such as bolt actions, machine guns, grenade launchers, ordnance, melee weapons, and even a couple joke items.
There are plenty of modes/maps to choose from, you can test your accuracy in the indoor range with an adjustable target, or try out the Sampler Platter which features several ranges to test different types of guns.
Or you could try the Take and Hold mode, where you locate and secure an area while fighting off armed hotdogs that want you dead.
Or if you want a horror experience, you could try out the Meat Grinder, where you navigate a dark, barren maze filled with robotic versions of condiments and meat that too, want you dead.
Anton does update the game a bit often, usually weekly or monthly so expect more content to be added some time after this review is made.
You are even able to play a more "realistic" VR version of Team Fortress 2, with the mercs as sausages!
As for performance, I rarely get lag spikes but I've got a powerful PC, the graphics are very good and they can be lowered down quite a lot, and other visual settings can be changed for performance if needed.
Keep in mind this is all singleplayer, and a VR set is needed for this game. There is no flat mode.
I highly recommend the game, even at full price.