You have an S60 platform phone.

It is two set of platforms in Nokia phones.
Nokia phones run on an O/S called symbian OS.
By platform you can compare it to windows XP and Windows 98.
In the latest phone like 6233,6270 etc.they run on s40 platform.
You cannot customize it much.
Where as the s60 phones like n70, nseries, eseries etc have a better os.
You can install softwares, run more than one application at a time, it's more analogous to a desktop computer. you call these a smartphone.

Your games are displayed in 1/4 of a screen because this are for s40 phones.