calc84maniac has ported Steins;Gate 8-bit to the original Gameboy and the TI-84+CSE Calculator. 0.40 covers the first 4 scenarios of the game (out of 7); but he plans to finish the rest of the game. He’s done a very good job porting them faithfully; so do take a look at his works and try them out!
Link to the Gameboy version here: http://gbdev.gg8.se/forums/viewtopic.php?id=191
Video preview of the TI-84+CSE Calculator version below: