I searched around for how do get these working and found only partial solutions. Here is what I did to get Doom and Quake working on my Centro:

1) It seems like you need UDMH to play some kind of memory trick on the Centro. I downloaded it here:
palmpowerups.com
Then installed it. I copied into the /Palm/Launcher directory of my MicroSD card, then copied it to the Phone (using Menu Key, Copy) then deleted from the memory card. Probably easier to just install to phone using HotSync.
2) I downloaded ZDoomZ and ZQuake from:
metaviewsoft.de
Then installed per the instructions on that website onto my MicroSD card. I used the full versions of Doom2 and Quake (.wad and .pak files) because I own the game, but shareware versions probably work fine.
3) I ran the UDMH app on my Centro and set to enable. Everything else I left to the defaults.
4) I ran ZDoomZ from the memory card and had to change some options. I turned off Music and Rumble. Make sure you assign the keys you want under Ctrls and remember how to get to the menu and exit the game.
5) You may have to soft restart (remove battery) to clear out the memory if the game crashes... not sure.
6) With Quake, I just turned off rumble in options. Here is the key though, In the control settings page, you have to reassign the UP and DOWN keys to the 5 way pad, even though the assignments look correct. For some reason it sees RockerUp as PageUp and RockerDown as PageDown. Weird.

Hope this helps other old school FPS players get playing on their Centros (I got mine free from BestBuy for Sprint!). I remember upgrading to a $2K PC so I could play quake... not I can play it on a free cell phone. Amazing.

Enjoy,
Ryan