Ah, cool! I thought open outboxes were a GDash invention. I wasn't aware that this is possible with the BD1 engine
Well, in this case, we should of course place one Rockford and surround it with 4 open outboxes. Then every input immediately wins. The only theoretical possibility for an easier cave would be one where even no input wins (after some time or, ideally, immediately.) For this, we would need an element which can push Rockford (into the open outbox). I'm not sure if there's any fanmade engine which features such an element?
An interesting mini project would be the challenge to make the easiest possible cave at Krissz's site, which has the following restrictions which can make it interesting:
- only one inbox (no immediately playable Rockfords)
- no open outboxes, at least one diamond must be required
- only classical elements and effects
A few properties I think the cave should have in any case:
- fastest possible speed (12 FPS) because 2 inputs are definitely necessary, and the quicker the cave runs, the shorter must the player be "concentrated" on pressing keys.
- no possibilities to fail (including infinite time which is possible)
- Hatching time 1 frame because every input which wins the cave with higher hatching time also solves the cave with lower hatching time but not vice versa.
But apart from these side conditions, it's not at all obvious to me what the cave should look like