Johnny got it!
But what I really want to know is how the clues lead you to this guess:
1. There have been a lot of games named Ninja Gaiden:
en.wikipedia.org
2&3: Definitely have seen this UI and power-up system before.
en.wikipedia.org
4: Animals seem to have it out for Ryu.
5. I was thinking man but we all know the real answer:
Hi!.....what's this? Dadz didz the sketchz four todai It's not...particularly...it's subpar. There. I said it. Yeah. Yeah...yeah. Mapz *ahem* The fans are expecting SOMETHING today. Hm. Marina. I have an embarrassing request to ask of you. .........look. I get that line of reasoning. I'm...
talking-time.net
Hi!.....what's this? Dadz didz the sketchz four todai It's not...particularly...it's subpar. There. I said it. Yeah. Yeah...yeah. Mapz *ahem* The fans are expecting SOMETHING today. Hm. Marina. I have an embarrassing request to ask of you. .........look. I get that line of reasoning. I'm...
talking-time.net
6: Deadly pitfalls abound (especially in the later stages).
7&8: Ryu can cling to walls but has to let go / jump off in order to move or climb.
9: Ryu is a martial artist and his sub-weapons are called ninja arts.
10. The game is split into multiple acts.
11. Well, maybe more spinning than twirling but Ryu spins when he jumps, his ninja star ninja arts spin and so does his spin slash ninja art
12&13: This is a reference to the scene from The Wizard movie which featured this game.
14: This refers to the difficulty and the name of one of my favorite songs from the game:
15: Ryu can destroy bullets with his
knife sword.
16: But not in the cutscene where he first meets Irene. (Hey, Ryu - Maybe you shouldn't have dismissed her as "just a girl".)