Rather than necessarily thinking of a human being involved which reincarnates into a robot how about instead work the robot reincarnating into different robotic forms. Below is one supposed list of the 10 levels of reincarnation. If you design a mechanical analogue for each level then you could literally evolve/devolve as you pass by the different levels. Arguably you could even design levels that require you to devolve a level or two in order to access abilities only available at that level in incarnation. (The game reasoning for devolution being: "in order to learn a piece of the greater truth i.e. leading to the development of the robotic soul"). If he should die prior to the boss you then send the robot to the start of a level or at the last check/save point and they are reincarnated into whichever form they have achieved at that time. You could build mini-meditation points in the game which enable the player to evolve if they are sufficiently high in karma - devolution occurring ingame as they commit unwholesome acts undoing their karmic buildup.
- Bodhisattva (an enlightened being destined to be a Buddha, but purposely remaining on earth to teach others)
- Pratyeka Buddha (a Buddha for himself)
- Sravka (direct disciple of Buddha)
- heavenly beings (superhuman [angels?])
- human beings
- Asura (fighting spirits)
- Preta (hungry ghosts)
- depraved men (hellish beings).
Hope this helps
Edit: Actually in thinking further - devolution might also be an act of choice but each level you choose to devolve might incur a karmic cost - so that when you reach a mini-meditation point you may not be able to evolve as high as you were previously thus requiring more work re-achieve the same point i.e. a spiritual corruption having been invited into yourself by devolving that must be cleansed.