Infazz from the XDA Developers Forum have just released a modified version of the GTA 3 file that tweaks the graphics and gives you the full effects. Check out the above image (you can click on it for a larger view) for the before and after effect after tweaking the GTA 3 graphics.
As expected, if your handset / device is not donning a decent GPU, you might experience slowdowns with this graphics update - so check it out first and give it a try. The steps are pretty simple if you want to do it on your own or if you prefer, you can grab the pre-made file from the source below. Make sure you backup your old GTA 3 graphics file before doing this - read the full thread below:
Source: XDA Developers Forum