i just bought Deus Ex for the PS2 and i want to share my opinion and review it a bit, when you want to call it so =P
Gameplay:
Same as the PC version, exept that some NPC´s have different positions, cause every map is splittet up into pieces, small pieces

Maps:
Now i go into detail, how they splitted the game.
First example is liberty island. They splittet it into 7 pieces
Docks + UNATCO HQ
Unatco HQ itself
North liberty
east liberty
west liberty
south liberty
liberty statue
PC? 2 Maps... PS2? 7 xD
They splittet it, using walls to block the view to the areal before. They use that everytime.
Some maps was rebuild, just for that. Battery Park looks nothing like the PC version, Hells Kitchen looks very different and MJ12 lab is different too.
But they added some new areals for exploring ore just moved the existing rooms to other places, who knows. They look different =)
Graphics:
god, is it busted.
The graphics are very low. some textures are lower than the lowest setting on the pc, so you can just barely imagine, what it supposed to be.
Charakter textures are so low, that the eyes just looks weird, the eyes are detailed. rest not :s..
The animations on the charaters looks good, but out of place for me.
When you shoot them in the face, they touch theyr face, when they die, looks great.
when they die, when you shoot in they torso, they touch theyr torso and fall. looks great too.
Your hands looks like the hands on the PC, nothing has changed. Some reload animations are different and the reload time on assault rifle and assault shotgun are much faster than they are on pc, but thats it here.
Controlls:
Well, its difficult.
here is, how it works:

VERY difficult at the beginning, i tell you that

sometimes you sit there and want to jump and then you think just that:
"err, how i jump now... *test a bit* ah ok there"

Sounds:
Same as the PC version.
Some sounds changed, like pistol shooting, assaul rifle shooting etc but in a nutshell, the sounds are the same (exept weapon sounds :P)
Problems:
Yeah problems. The PS2 having trouble handling Deus Ex.
when you first start the game, you see, what i mean. FPS just drops, like when you look to the statue of liberty from the dicks, they drop to 15~ ore so, sometimes it drops under 10 ore 5 (under 5, when you plast the sh it out of the NSF warehouse =P).
Sometimes, the NPS´s see you, when you are miles away and start shooting, so you stealth is gone ore busted for that moment.
but the KI is stupid, like the PC one, so its no problem. just hide a few seconds and they lost you.
Changes:
When you talk to someone, the NPC´s stopped shooting you on the PC version, on PS2 they shoot you but the conversation still goes on.
When you read a book,datacube ore a newspaper, the gameplay stops and you can read it for hours without getting shot. PC version doesnt stopped the gameplay, so NPC´s can shoot you, while you reading stuff.
When you found a Login/Password/Key Number ore something, the game automaticty use that. that means, you CANT type the password, you have to find it.
Inventory is totaly different.
You can hold 4 main weapons (GEP Gun, Pistol, LAW, Assault Rifle, Sniper etc)
You can hold 1 x 4 Hand Weapons (1 Slot with 4 underslots, where you can hold total 5 weapons like Knife, Baton, Crowbar ore DTS)
You can hold 1 x 4 Small weapons (Roit Prod, Pepper Gun ore Mini Crossbow)
You can hold 1 x 4 usable items (Soy Food, Vial Zyme, Soda etc)
You can hold 1 x 2 other items (Multitool and Lockpick)
You can hold 1 x 2 Medical Items (Medkit and Bio Cell)
YOu can hold 1 x 4 Grenades (LAM,EMP,GAS and Scramble)
other items like Augmentation Upgrade canister, Augentation Canister ore Weapon mods are in a other menu, weapon mods can just be taken, when you choose your wepon and use the "customize" button.
Augmentation Canister DONT need a Medbot to install. you cn just go into the Augentation Menu, choose your Canister, choose the Aug and there you go, its installed.
Health is on PS2 just a 300% long bar, no arm,leg,torso ore head, just a Health bar.
health bar doesnt recover without medkit.
Medbot heals 100% of your energy now
Repair bot heals 100% of your bioenergy now
There is NO Key on the PS2 version. When you find a key, you just have to Open the door. it will unlock automaticly
Okay thats it for now, i doesnt compledet it yet, but i will in the next few days.
hope you all can understand, what i want to say here.
Sorry for my bad english, but you dont know it better from me, so doesnt mention it =P