PS2 FPS Game with Grandma Character

Well,I looked through all the characters in that game,and there's no grandma. Also,from what I remember of this game,it didn't have that many characters and the character select screen was different. I would guess that it had maybe around 12 characters,and the character select screen was just a normal grid showing all the characters on the screen at once,not a slider. Another thing I can sorta remember from the game was that it looked kinda dark,like it seemed as if you were using a flashlight to see what was in front of you all the time,everything looked dark. The only map I can really remember tho was this warehouse map,which is just your standard warehouse with all the assorted boxes,the big shipping containers and all that stuff,so the darkness may have been only on that one map.

This barely fits your description but just for the sake of throwing it out there... was it Worms 3D? The playable characters were all just worms, it wasn't splitscreen, I don't remember if there was a warehouse level, and it was only first-person while you were aiming your weapons, but it does have a Grandma-type character... that you could use as a walking explosive. www.models-resource.com/gamecube/worms3d/model/6058/ (can't seem to find any gameplay videos of the weapon in use though)

Since you mentioned that the PlayStation 2 First-Person Shooter game in a Multiplayer mode that the elusive "Grandma" character might be featured in is Cold Winter, I decided to do some research on that game and I find out that it's a 2005 First-Person Shooter game developed by Swordfish Studios and published by Sierra and Vivendi Universal Games for the PlayStation 2 and a planned port for the original Xbox (though a port of the game was cancelled). I have included the scans of the PlayStation 2 version's box art and back from GameFAQs for reference reasons.

I'm not sure if this is the game where the "Grandma" character was featured as a selectable Multiplayer character, but I hope this video of a Death Match on the PlayStation 2 version can re-jog and refresh your memories (I'm aware that there are more gameplay videoes of the other modes in Multiplayer on YouTube, but I'm too lazy to search for more).

 

Well,sadly it's not Cold Winter,I looked through the characters - no grandma there,nor is there any possibility of unlocking a grandma character somehow. Whatever this game is though,it looks pretty similar to Cold Winter,similar graphics style. I think me and Sandman probably played the same game,and it came out on both platforms.

Guys,I've actually managed to find the game! It was Syphon Filter 3. Looks like I got a lot of details wrong,like it's third person instead of first person,and it's for the original Playstation. Just goes to show you how your memory gets fuzzy over time. One thing I'm 100% sure of tho,is that we WERE actually playing on the PS2. Must have been using the backwards compatibility.