I'd like to make some questions to whoever has a Samsung I5800 smartphone.

Does it have a GPS support for I-GO , MLS Destinator , Ndrive etc. or it goes only with Google maps through the internet?

When is connected to the PC via USB cable, is it recognized as an external hard drive, or it needs a complicated procedure like an Iphone with the Itunes application?

I've seen a Samsung Galaxy model which has a unique screen unlock feature by connecting dots in a shape preset by the user. If the shape is not correct the screen won't unlock.
Does I5800 has this feature?

I have some game titles which I'd like to know if they are compatible with Samsung I5800
ScummVM emulator
Duke Nukem 3D
Quake 2
Tower Bloxx Deluxe

As the i5800 is an updated version of the Galaxy, running the same OS, then it will support everything the Galaxy does.

For information

I've seen a Samsung Galaxy model which has a unique screen unlock feature by connecting dots in a shape preset by the user. If the shape is not correct the screen won't unlock.

This feature is NOT unique to galaxy phones, but available to all Android powered devices.
My HTC Desire also has this.
It's available in Settings > Security > Setup Screen Lock.
From here you can choose Pattern, PIN or Password.

More details here: http://www.mobilegazette.com/samsung-galaxy-3-apollo-i5800-10x06x17.htm