Low complexity.
Heh, you could arqgue that Rogue itself was not very complex. But I get what you mean.
Hyper Rogue has a Tactical Mode, by the way, in which you can stash orbs in your inventory and use them when you need them. One thing I don't like much about Classic Mode is precisely that you can unlock lots of cool orbs during the game, and not have them around when you need them.