I am working on a FPS player code. And I coded almost everything it needs but I got a problem which is:
When player walks on a terrain, because of GLIDE, player walks so easily on the world even climbing very big hills. It should be harder and sometimes it should be impossible, player shoudln't be able to climb that big hills. How can I do that?

Waiting for help, thanks...

have a look at disable_z_glide, move_min_z and move_friction.

Hmm, I didn't know these, thanks! But I tried them and couldn't get them to work. My code is:
Player can still run through big hills with that code

don't use aabb collision detection.

Allright, I tried without USE_AABB but still the same result They don't effect in any way...

Try having a look at this thread. It may give some ideas or answers.
Here

Thanks for the idea, I tried that:

me : It is a little object that always in front of player(almost 70 quants away). And I am getting the second c_trace vector from it's coordinates.So, player sends a beam 70 quants away.

I wrote a on a panel. But it returns always big values. And sometimes the numbers it returned don't make any sense.

Ive never used this but leave your panel showing "a.tilt"
but slot in this line before the displays...
a.tilt = cycle(a.tilt, -90, 90);
If I understand 'c_trace' and 'normal' and 'vec_to_angle' correctly,
"a.tilt" is 45 = 45 degree slope away from player
"a.tilt" is 00 = flat wall-like structure.
"a.tilt" is -45 = 45 degree slope toward player (overhanging cliff)
I may have the calculations out by 90 degrees though.

Have you tried the standard walk code from the manual? I think it makes the player slower on steep hills, when you adjust that parameter you can also make the player stop when the hill it too steep.