Ive tried the Demo of Call of Duty 2 from Click gamer and that happily ran on the Touch Diamond.
Plus good ol Picodrive runs very smoothly. (on my Touch Dual it ran very sluggishly so I think the graphics acceleration is working on the touch diamond as PicoDrive runs very smoothly, sonic on your phone, spot on!)
Also tried FinalBurn which runs Capcom game roms (google to see what im talking about) Got Streetfighter 2 working on my Diamond and it looks and plays pretty good (apart from the lack of hardware buttons to assign it runs smoothly and at proper speed)
Be interesting to see what other games people know work.
Incidently tried MicroPool and that wouldnt run (also quake but I think thats something im doing wrong as it displays the Quake interface but when i quit out of it shows the screenshot of Quake itself, weird)
Overall im happy with the screen quality and the games that work so far, just gotta find some more now!

Edited by Tomchap, 30 June 2008 - 08:53 AM.
Tom
Please checkout these links:
My brother is cycling 1017 miles for charity, please take a look and sponsor him. Thanks
Click to view the Blazing Saddles 2008
Quality Webdesign with the personal touch
visit mooedia
Have a listen to my music and see what you think
listen to mixed up
Phone History:
SPV Classic/E200/C500/Nokia 6250/Ngage + QD/XDA + II/SPV M2000/T610i, Razr V3/O2 XDA mini s/M5000/SPVM3100/C600/Ameo/Prada/Viewty/Touch+Dual+Diamond now iPhone 3G 16GB