At the HG101 Forum Robert Seddon has noticed an interesting topic related to the unseen world. The question from the OP is: what are some unused ideas in games you can think of that was used in other games from the same company? Even if there are not many replies to the topic, we can read some interesting info:
Technos Corp.’s Return of/Super Double Dragon was originally supposed to have a scene in mission 6 where the broken bridge would fall apart, and after sailing for a bit, it would arrive at a steel door behind the waterfall where the boss of that mission emerged from. The door lead to the final boss’ hideout. That idea was later incorporated into Shin Nekketsu Kōha: Kunio-tachi no Banka, also from Technos Corp.
The arcade version of Border Down has a flock of birds at the beginning of stage one. G.Rev thought it would be interesting to make them not appear in the Extra mode, but accidentally took them out of the entire Dreamcast port at the last minute. (They’re pictured on the back of the game.) The birds were added to the beginning of Under Defeat as a belated gift to the fans.
Early demonstrations of Mass Effect showed a dialogue system where Shepard could enhance the conversation physically at certain points, but it got cut. They’re building that now for ME2.
Do you know more unused stuff that were later reused in other games?