HI!
I'm the author of Unofficial Cave Story : Return to World that I presented to NEO Compo 2008.
The game is simple : There are 3 type of games

--IN TITLE MENU PRESS START TO PLAY--
1) Catch the mimigas that fall from the sky,
2)Ride the Green Tea Dragon,
3)Escape From the Boss.
They are very intuitive , however this are the controller button

Button L for change level  (at any time)
BUtton R for 2 PLAYERS 
directional cross for moving 1 player
square , circle , triangle  for move 2 player
cross for confirm level selection

i hope that this game entertains you.

                           Bye , Leviadragon 
                           ps : sorry for my bad english xD!