Hello. What mean this PG13?

Another question, can i use edited graphics of rtp? Like recolors, or combine two tilesets for example.

PG13 is a movie rating used in the United States.  In the gaming industry, it would be between E10 and T. 

With potential edits, some may use those found in the forums.  Thanks for asking.  It helped me make the decision to add another rule.  To keep the spirit of this being a purely RTP game jam, edits will not be allowed.

are title screen graphics to be rtp to was just checking

As with the previous RTP only game jam, the title screen images are to come from those in the original RTP folders.

also how long does the game need to be wasnt mentioned or i missed it

It was answered in another question.  I recommend it to not go over 30 minutes.