Haroldo has been working on a new Master System game the past days.

Release notes:

Well, here’s a new version, going back to the first person engine, and beginning implementation of a RPG-styled battle system.
The green “things” you see on the screen are supposed to be enemies. Once implemented, it’ll be the old traditional game mechanics: The player will walk around for a while, and then, suddenly the enemies will appear in front of him, and then the game will enter battle mode.
As can be seen, there are only two enemies on screen. That’s because of the 8 sprite per line limit, even though, so far, little less than one third of the maximum sprites per screen are in use. Later, I intend to experiment with combining sprites and backgroud tiles to get around this limit. Adding some flying enemies would also help getting around this. =P

http://www.smspower.org/forums/viewtopic.php?t=10839&start=20