For those going to try the portal:
Until enemy lv20 you'll breeze through the map as you please, the first few battles can be instantly won by just tossing 3 artillery shells on the enemy commander.
After ~lv26 they'll just repeatedly throw 5* tanks(I suspect boosted/with emblems) at you until you get a lucky break where they don't AoE your leader down before you can get the deathball rolling.
Fun? Not really. Not to mention you're basically forced to get 4* or better tanks to compete at enemy lv30+. Which isn't -difficult- if you have 4 construction slots thanks to the prereg goodies, but it DOES mean a rich get richer cycle where new players that aren't planning on shelling out big will gradually keep falling behind in the rankings.
For me the portal feels like a wasted opportunity. Enemy design isnt inspiring or clever, it LITERALLY chuck 5* units at you until it runs out/you lose, whichever comes first. The rewards for anyone that isn't willing to grind to the max/throw money at it are painfully average.
I understand that the portal is pretty much copied from the mobile version, but come on. It could have made for a great launch event setting. Throw some corruption lore bits in, rescue some tanks trapped investigating/go investigating and find non-hostile corrupted tanks, allowing you to introduce a tank or three to the roster and then introduce ladder rankings once people have had a real chance of getting their rosters together.
On the bright side, it gives me something to dump my oil glut in I suppose...