[ambiate]

From a player perspective, Zelda is harder due to: --Larger world with set of objectives which must be completed in some order. IE: You need the bow, before you get the lance, before you get the ice wand. A program could endlessly wander in the wrong temple for centuries before it decided it exhausted the whole area. (Not to mention the hidden walls/areas). ++Mario levels are completed in a mostly linear fashion (ignoring the short cuts).

--Limited resources. Bombs, arrows, etc. ++Mario can always jump/squish, and fireballs are infinite.

--Game changes as items are acquired. A block may be liftable in phase3 of the game, but not in phase1/2. An area may drown you in phase1-4, but may be swimmable in phase5. ++Mario death is always death.

My number one reminder why Zelda would be harder is that temple where most of the walls/floors are bombable and drop you back to the bottom (except one). A computer learning without manual training of some sort would be very interesting to watch.