The atmosphere & immersion are still unmatched after more than a decade.

Soulful soundtracks, lethal weapons, intense gunshot & artillery sounds, no-nonsense supression system, fast paced, player models either screaming loudly in agony or calling for their mother when killed, a color palette reflecting the inhumane atmosphere of war....

Hopelessnes, anger, fear, sorrow etc. are pretty normal while playing
(All the PTSD related memes tied to this game are there for a reason)
EDIT: Now that Ive read it again, I think I might have to consult a psychologist

Good:

- Size of maps are optimised for 64 Players (about 2 weak platoons) fighting with each other
- Map restrictions which avoid spawncamping & running around enemy defences
- No chaotic cluster♥♥♥♥ matches like in other shooters due to oversized maps because the Devs mistook Regiments for Platoon combat sectors
I cant stress it out enough how important this problem is for the gameplays sake
- Pacing speed is a good mixture between fast & slow
- Realistic Damage Models (almost every hit is lethal)
- Realistic Weapon behaviour
- Accurate places in Stalingrad (Mamayev, Pavlovs House etc)
- Heart attacks (very atmospheric)
- Accurate Tank interriors
- Teamplay is being rewarded
- Beautiful Soundtracks
- Online Campaign Mode
- More Heart attacks
- Roles & equipment made after historical platoon structures

Bad:

- Pistols have very low stopping power
- Tank maps are rare (community's fault)
- Teamkills are not uncommon
- Can get frustrating
- Low player numbers