OK going on that id have to say its just down to specific games then. Most likely some of your games wont work on you phone due to the age of the internals.
You could always try using a task manager to kill everything but the game before you launch it but i'm not sure how effective this will be.
Technically the processor and graphics chip in your phone (Qualcomm MSM7227 with adreno 200 graphics) has been around in some form since 2008 so its getting on a bit, and I'm not surprised some of the games are crashing tbh. Plus having only 256mb of RAM to play with in the phone is not going to help.
The only thing i can suggest is to maybe root the device, apply a custom rom that pure stock android and maybe overclock the processor. you should be able to clock it up to 800mhz from 650mhz with no trouble as thats what the processor is rated to anyway.
The folks over at http://forum.xda-developers.com
can probably help you out with this, if you decide to give this a go (i have no clue about rooting so I can't help i'm afraid), just back everything up before you do if you decide to do this.
Personally I would just shell out for a less outdated phone though. Would be better in the long run for you.