I am maybe boring but I like to dig around looking for games
. Maaaybe one of them could be portable.
What about this one:
http://www.knightsgame.org.uk/Knights is a multiplayer game involving several knights who must run around a dungeon and complete various quests.
It was first time ported to Amiga. Game play is made something like Spy vs Spy on C64 where you lay traps for other player and try to escape the dungeon full of other death traps and zombies... Even your corps can return as one
.
It supports single play and separated server (for GCW users or GCW-to-Dingoo users maybe?).
Pros:
Graphics are resizable.
Author is still active(last post on 31. Dec. 2012) and easily reachable (through forum, mail or blog) and could help with porting or even make one himself.
Source available and written in C++ following GNU GPL licence.
Needed just few buttons for actions and movement
Cons:
Not sure how would it look on 320x240. Didn't have the time to try to build one. Originally it was made for Amiga, so resolution doesn't have to be a problem.
Not sure if the server is needed to play single play and if it is, how to make it work with Dingoo or GCW. Is it even possible?
It is a hot seat game from the beginning, how is it playable with only half the screen used(looking from the pictures)?
Control panel for starting the game is made for OS with GUI in mind. Is it portable to Open Dingux?