Graven is half combat and half exploration. Both halves are bad.

For starters, combat simply doesn't matter because dying and starting from a checkpoint doesn't respawn enemies or even heal bosses, meaning you can just throw yourself at the obstacle and always get through eventually.

Second, your base movement speed is awfully slow. You can sprint, but there's a stamina meter that some other actions also take away from.

Third, the feedback is weak (due to bad animations) and inconsistent. Enemies get staggered on occasion, but not all enemies (with no clear logic behind which do), and not reliably, ranged weapons have bad accuracy, sound effects are confusing, it's hard to tell whether spells are even hitting the enemy, no weapon is fun to use.

Fourth, switching between items is annoying. Putting them in the item bar is a weirdly inefficient process by itself, but then you have to sit through every single item swap animation to get to what you want, and they're so different in length that it's easy to not even end up at the item you wanted.
It's made worse by the inclusion of two items that are forced into your hotbar at all times, adding to the clutter.

As for exploration, it does have some redeeming qualities. The level design is pretty nice - pretty open ended, with interconnecting paths and times where you're shown parts of an area from different perspectives.
The environmental art is very solid as well.

The issue is that it's never clear what the game wants from you - key items are placed in awkward places, there's no way to tell if you've got everything you need, whether you should explore more or leave the area, and your current objective is just a mystery a lot of the time. Doesn't help that backtracking is a little annoying due to the stamina system.

So I wouldn't say its a 'bad' game, but its just not that engaging. Aesthetically, very cool. I really liked the world and enemy designs, the weapons aesthetically were cool, the level design mostly flowed together well. My biggest issue was the impact and feel of the weapons was just, very unsatisfying. It didn't help that the story that was kind of being told was really generic dark fantasy stuff. It could be totally fine, and if the actual combat was more than very basic this stuff would probably even add to it for me, but when the combat is so boring I tend to focus on other aspects more, and it makes the issues more glaring.

Not a bad game, not good enough for me to want to finish it after playing for about 3 hours

Started off strongly with fun puzzles, nice music and brilliant level design. Then it got held back by the janky and unbalanced combat (some enemies would still damage you even if you landed a parry) where the most effective way to kill most enemies was to whack them with your stick or shoot them if they are flying enemies. As you progress, the nice open levels become an absolute chore to navigate as the game expects to excessively backtrack with Hexen-like hints on where you have to go.
It shows amazing potential but needs more time in the oven.