Fairly straightforward tank. It has a pikes nose front (3D triangle type thing) and as such it's automatically angled by just facing straight towards an enemy. By angling (turning the tank left/right and wiggling) you are effectively making the pike's nose weaker by flattening one side to an enemy. In an effort to angle the lower plate you will weaken the upper glacis and the lower plate will still probably be weak.
How you play this is always being mindful of the lower plate. The lower plate on the 252U is huge and therefore easy to shoot and quite easy to pen. When you drive towards an enemy ask yourself, "Do they have line of sight with my lower plate?" If so try to find something to cover the lower plate. If not, then your best bet is to try and angle. I find by going hull down (hiding hull behind a wall or terrain) works best, but enemies can still pen the cupolas so be wary. When fighting an enemy below you try to point your tank "down." Enemies, below you can easily shoot your lower plate. A good example is a river. Rivers are lower than the surrounding ground so enemies can shoot your plate, try to go to the edge of the riverside where the terrain dips down and angle the lower plate downwards. This lets them shoot the cupola but the cupola is a lot smaller than a giant lower plate. Though pike nosed tanks weaken by angling, the 252U has like 400mm upper plate armor (if remember right) and a bit of angling won't hurt as it will increase lower plate armor, but not weaken the upper glacis too much. If you can, always face hug enemies. When face hugging the only threat is being penned in the cupolas and after firing just wave your gun in the air back and forth to possibly barrel block a shot. Also, try to shoot on the move more than aiming in and shooting. For an odd reason, I find shooting on the move to be more accurate than fullying aiming and I use double rations, shell velocity boost, and the other aiming speed increase equipment. Due to the tons of upper glacis armor, you can easily side scrape (while trying to hide lower plate). I've no joke, blocked 3k damage on less than 20 HP and held off an entire flank just because I hid my lower plate and pointed my whole tank forward so HE damage wouldn't splash me.
You want to focus on the main issues of your tank.
TL;DR: Always be mindful of the lower plate, try to face hug enemies, and shoot on the move more than stopping to aim. This tank can steamroll enemies. Don't be scared to rush out and catch a lone tank by face hugging. This tank can easily bounce tier 9s and even some tier 10s if played right.
Frontal WS (Weak Spot(s)):
1. Primary WS: Lower glacis
2. Secondary WS: Cupolas on the turret
Pros:
1. Insane upper glacis armor
2. Decent mobility (around 35 KMH forward)
3. Oddly super good on the move shooting accuracy
4. Face hugging beast
5. Somewhat troll side armor (like the IS-5)
6. Pretty much a n00b friendly tank; as long as you somewhat have an understanding of Soviet heavies you should be fine
7. Sides and rear and decently angled (like the IS-6). Ability to get some rear bounces
Cons:
1. Really big lower glacis
2. Aim circle is huge
4. Long reload (13.1 seconds (with rammer))
5. Seems to low roll often (around 380 damage) but when it high rolls it almost always is around 410
6. Typical Soviet gun depression (It's like 6 degrees or something over the front)
7. Weak to CoD (circle of death) by faster tanks. The rear is a T49 HEAT magnet.
8. Because people can't pen the tank, they spam HE, especially T49s, who deal almost 250 per splash