This is like what happened in Metal Gear Solid 2. They got rid of Solid Snake and no one was very happy.

People really wanted to play as Snake and they only got the short(ish) Tanker mission. I suppose you probably could find some way to do it right, but be careful.

If this is some kind of RPG, see that the human gets back on active party, problem solved.

If it''s an FPS or 3rd Person Adventure (3PA?), then see to it that the human still has a role, like rescuing the alien, or performing in puzzles, etc.

Point is, to keep the players from being angry about losing the human, you can play games with the participation rates of the characters and let the players feel that each character was evenly used. That is unless the story calls for the human dieing. Then I can''t help you.

maby you cold intergrate the two characters together, i.e. they both join forces, as the human and the alien have things to gain from the deal:

The human: survival and a position where he can have some power and have new technology(maby a colony of humans survive, not just one).

The alien: All of the knowledge from the humans of the world and, maby, even some technologies and things that the human has/can do that the alien cannot/does not have

For example:

The alien may not have a ability that we,as humans have.

I hape this was usefull

Another game that did that which I liked a lot in the old days was Dragon Warrior 4. You named the main dude at the very beginning, and then suddenly you go into chapters 1-4 where he doesn''t even appear and instead you''re playing various other guys. In the end chapter everyone all got together for one big showdown with the bad guys, and by this time your main char was grown up because it took so long to get through chapters 1-4 heh.

Anyway, you could very easily have your human and your alien perform different functions. For instance if there''s any human settlements left, your human will hafta interact with them because the alien would probably just make them run or shoot him. Also maybe your alien is too big to fit into some places, even if he does have super-technology. Or maybe your alien has to hibernate, or can only survive in the planet''s atmosphere for x amount of time without having to go recuperate in his ship, etc. etc.

Oh and another thought. In the Mana/Evermore games, you frequently have to leave one guy in one place, and then go bring the other guy into position to do something else, and keep switching back and forth. (For example one guy has to stand on a switch while the other guy goes through the door the switch opens.) It''d be fairly easy to do something like this, and add lots of puzzle opportunities if that''s the type of game you wanna make.