well noo, because its all programmed in ASM (assembly programming). See the processor for the TI is the same as the processor for a Gameboy. And for gamyboys like TI's they use assembly to create moost of the games. Yes basic is used for most math programs but it is incredibly slow for any form of Graphical games. Sure if you want to make a cool drugwars clone go right ahead and use basic. But if you want any game with large amounts of speed use Assembly. Assembly is a very complicated and confusing language. It is extremely repetive and the code looks like u need a secret decoder ring to read it. I know a little assembly but i haven't tried much. If you want to learn alot more about calc programming i suggest you check out
http://www.ticalc.org/ they are the number one place for calculator gaming and programming. Now that said, to run ASM games you must have a shell. Because asm is not compiled it is just run. I have written a shell for TI-86 and there are many more available on ticalc.org's site for any TI calc except like the ti-81 or 80. any of the really cheap crappy calcs don't have a easy way to run assembly and they're processor is incredbly crappy. Now if you'd like to see some nice Basic programming i have many prog's written the problem is your TI-83 is pppoooooooo. TI-83's won't run ti-86 games or programs. Get a 86 or an 89 i know its more money but its so worth it. The screen resolution is better, the refresh rate is alot better the processors are faster ... they're just better. You can go and download Super mario and plain jump the best games out for calc for you ti-83 but the mario for 83 kindof sucks. i have an 83, and a 86 along with a casio cfg-9700 so if you need programming help for any of those i can be of assistance.