Mama Bear has been documenting the festivities all day ... and just like any other Kardashian shindig for their children, this one's no different in how above and beyond Khloe went to make True's day special. Seriously ... their pad's totally decked out with decorations.

Indeed ... it would appear Khloe and co. went with a feline feeling to ring in the big day -- and True's loving it. Some of these vids of her soaking it all in are pretty heart-warming.

Not only are there a ton of cat party favors all over the place, but some actual kittens have been brought in as well ... so True and all of her cousins/friends have more than enough to keep themselves occupied, on top of all the other activities around.

There's a trampoline, a face painter, a ball pit with stuffed animals and prizes, a jump house/slide -- and there's even some kind of anime cat animal character in costume who's all set to boogie ... and which True is willing to help with as well. The girl gets down!

Oh, and her actual birthday cake was something behold too -- multi-layered, and intricately designed. Also, very on theme for what's going on around them.

Like we said ... it's kind of the M.O. for the Kardashian moms -- they go all out for their kids, and Khloe is no exception. These are just a handful of snapshots of the scene, but if you peep her IG Story ... you'll see the full scope. The place is like a kid wonderland out there.

It looks like some of Kim's children are also on hand ... including North -- who gets a little mouthy with her aunt about her thoughts on age 4 -- plus Dream and other little ones who are all running around and having a blast.

There's toys, there's games, there's attractions, there's music ... what else could a 4-year-old want in this day and age???