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Dennin-Aleste: Nobunaga and his Ninja force (電忍アレスタ) is a vertical scrolling shoot-'em-up developed by Compile exclusively for the Sega Mega-CD. Outside of Japan, it was released as Robo Aleste.
It is part of the Aleste series of games, and is meant as a followup to Musha Aleste. Strangely, this is one of only two Aleste titles to ever use the name outside of Japan; the other is Super Aleste.
Many of the base mechanics come from Musha. You control the flying robot with the directional keys, and change the speed of movement with . fires your main and sub weapons. Main and sub weapons work much like the previous game; collect "P" chips to add more kunai streams to your main weapon, and collect one of four colored orbs to either change or powerup your current sub weapon. Blue is a piercing laser (like yellow from Musha), green fires shurikens with a wide range, brown is for bombs (somewhat like red from Musha), and yellow turns the two options into a rotating shield (like blue in Musha) while also giving them limited homing capabilities.
The way options work is the big mechanical difference from Musha. The robot now comes with two fixed options in front of it at all times, which can never be destroyed. The options still absorb enemy bullets and cause damage on contact, however. Not only that, but your sub weapons are now fired from these options, allowing clever players to do additional damage. Finally, you can even perform a limited charge shot with the options by holding for a brief moment; note that holding also fires your main weapon, but not your sub weapon.
Unfortunately, like many console-exclusive shooters, there's a silly scoring exploit that makes the score counter irrelevant. Similarly to Seirei Senshi Spriggan or Super Aleste, powerup carriers reappear infinitely during boss fights, which are once again not time limited. A short-range weapon such as the brown sub weapon will keep you going for a long time. You can no longer fire the sub weapons separately from the main weapon as you can in Musha, but careful maneuvering should be able to get around this.
Robo Aleste versions of the game contain small balance changes to make the game easier. The big two changes are that dynamic rank does not rise as quickly, and that the yellow weapon has been buffed.
Stages
Dennin has a grand total of 11 stages, making for a very long game.
Stage 1
Boss: 飛竜 (鉄)
Stage 2
Boss: 武者王 (今川 義元)
Stage 3
Boss: (上杉 謙信)
Stage 4
Boss: 飛竜改 (鉄)
Stage 5
Boss: (武田 信玄)
Stage 6
Boss: (長宗我部 元親)
Stage 7
Boss: (島津 貴久)
Stage 8
Boss: (冴刃)
Stage 9
Stage 10
Boss: (毛利 元就)
Stage 11
Mid-Boss: 火竜 (鉄)
Boss: (Astaroth)
Versions
The game was made easier for the release outside of Japan, e.g. Aleste's yellow homing orbs became much stronger and the steady increase in rank was toned down. The NTSC-J version had plenty of character dialogue stored as Red Book audio tracks on the disc, but many of these tracks ended up being unused. The respective dialogues simply appeared as text.
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fires your main and sub weapons. Main and sub weapons work much like the previous game; collect "P" chips to add more kunai streams to your main weapon, and collect one of four colored orbs to either change or powerup your current sub weapon. Blue is a piercing laser (like yellow from Musha), green fires shurikens with a wide range, brown is for bombs (somewhat like red from Musha), and yellow turns the two options into a rotating shield (like blue in Musha) while also giving them limited homing capabilities.
for a brief moment; note that holding 
