Hell Let Loose, released less than one year ago, is a first-person shooter set in the WWII featuring tons of realistic elements from animations to how the weapons work. The game is in early access, meaning that developers are working constantly on it, and they even have a plan for future content updates, which you can see here [pricemate.com]
So, what is Hell Let Loose right now? The game has its basics set and they are already playable, and as developers have been showing in their last updates, they truly consider players' opinions and suggestions on how to keep improving it. The game has a smaller community than the most popular FPS games right now, however, it has an average of over 1000 players in the past three months and during weekends, servers are mostly populated.
Once in-game, be ready to talk and work with your team to achieve victory. If you're a newcomer, still figuring the guns and what works best for how you enjoy playing, don't worry. The game's community is friendly and you can take your time. Be aware though, the game won't hold your hand, and working with your team is a must.