Games can be complicated, you know Search for some books about objects pascal, learn about classes, try to rewrite your tp source to fpc (see their page, there is a section about it). Meanwhile, see the Forums sessions, especially Freepascal Basics and Game Libraries and Components. Then choose a library with you would like to use, have some patience installing it and try out the demos.

For 2D stuff, I recommend these two:

Jedi-SDL
Phoenix

They have good demos, they are easy to understand. You'll find their developers here at PGD