The winning entry from the Bonne Mecha Event was the Donner Wels, chosen primarily for its "impressive repertoire of moves and each of those moves' apparent versatility." Refining the design was not merely a matter of tweaking visuals and scale, but also figuring out which attacks to use, and how, and when, and balancing the difficulty of the battle. The developers chose to work the attack patterns based on how close the player is to the mecha, using three distance ranges of 0-10m, 10-20m, and 20-40m. They also added "Big Moves" for the player to be extra cautious of.

To increase the "Bonne Mechness" they gave the visual design a major overhaul, and added a servbot-related gimmick.



A yellow box was used as a means of working out scale. Initially they settled on a height of 4 meters, but the designers pointed out that Tron would be scrunched in such a machine, so they upped it to 6. With the mecha's size decided, they determined how large to make the room where the battle takes place, and then the environment began to take shape.


After a lengthy process of working in all the special effects, balancing the difficulty, and tweaking endlessly, the Donner Wels was finally finished. The battle was shown extensively in screenshots and videos, and was to be the final mission playable in the MML3 Prototype Version that was never released.