Starving Symbiosis by Lasty 2014-08-27T04:19:00
Having not read your instructions and just diving right in, it took me until my friend in the underworld died for me to realize it was two separate people and I wasn't just 'warping' between the worlds. At that point though it clicked! and I really liked this idea that the only connection you have to your 'partner' is this shared portal that items can be passed through. I think this central mechanic has a lot of interesting potential and I think the basic way in which you've explored it with money and shops demonstrates that well.
I would have really liked to have actually seen no money _at all_ in the surface world to make the two worlds truely symbiotic. As in my first play it was fairly easy to keep the surface player alive, and it was only the underworld player that truly had a dependency on the other for food supplies. This sort of makes the relationship seem more parasitic than symbiotic, but the abundancy of the money underworld does make up for this well enough to still express the themes you were going for.
The controls and general feel was a little slidey but they were good enough to express this key thing that you were getting at with the game which was this co-dependency and shared portal mechanic. I think however the general control experience is what I would put a lot of focus into if you do decide to take this concept further, and I hope that you do!
I really really like what you're exploring with this game, and even though you say you had much more you wanted to add (didn't we all!) I think you get the essential message across reasonably well! A lot of potential and a cool use of the theme.