Heartwarming / DonPachi

• Read the initials of the default high score table in DonPachi, top to bottom then left to right. They spell out "TOAPLAN.FOREVER", a tribute to the now-gone Toaplan, which was one of the most influential shmup developers and whose employees would go on to join other shmup-developing companies, including CAVE.
• Toaplan would get referenced again in dai ou jou, where in keeping with theme of naming the songs after various shmup developers, the theme of the very first stage is called "Tōa" (東亞). As in "Tōaplan" (東亜プラン). Even eight years later, the CAVE team had not forgotten about them.
• Leinyan's ending in DaiOuJou. Not even the government deactivating her and locking her in a research facility is able to stop her being with her love, her human pilot.
• The true endings of SaiDaiOuJou that occur for each character after you defeat Hibachi has your Element Doll vowing to stay by your side no matter what.
• If you think about it, The Stinger in the Xbox 360 mode of SaiDaiOuJou may have the Pilot coming to comfort Saya or Hina being rebuilt and reuniting with Saya, judging from Saya's smile at the end.