If you aren't a speedrunner, I wouldn't even look at 10 Second Ninja. I decided to buckle down and really work at the game, and quickly completed it with some effort. The full content is around 4 minutes
long, with later levels only adding portals and enemies that take two
hits to kill. The only appeal of the game is finding routes to optimize times.
The game is built on Game Maker, I only knew this after the 2nd cutscene gave up a Game Maker error report and crashed the game when an image couldn't be found. The program seems to take process priority along with nearly 500MB of RAM, slowing the Desktop and all other activities if you want to Alt-Tab. FPS is good, and I assume the high priority is to make sure the clock is accurate.
Controls are simple but inconsistent, not really fitting for a precision platformer. The sword hitbox can be gigantic at times, even allowing some kills through walls. Normal ground behaves more like Ice, while Ice really didn't give me much issue, maybe because I finally got the hang of controlling this ninja on rollerskates. Sometimes the ninja would auto-run after restarting, while other times it would ignore my inputs (mostly in the Hard mode 100% run, wasting precious time). The 10-second max means most levels are very limited, with only 4 of the 40 levels spanning beyond the screen. I'm kinda shocked a ninja in a platforming game can't wall-jump, while a cube of meat can.
The game requires Stars to progress in the game, so expect to repeat and perfect levels from the start. Beginners are not welcome here, and the developer even insults you if you happen to beat the game 100% without impressive stats. At least the community seems friendly, with some helpful videos on strategies to complete the game. I don't know if the developer cleans time records, but there's a cheater with a 100% time of under 5 seconds that needs wiped. At least the music in the Bonus area was really good.
Overall, the game got a bit better, but it's too one-dimensional. Super Meat Boy, Stealth Bast Deluxe, and other platformers allow speedrunning without limiting level design and cutting mechanics. 40 short levels, limited variety, and no level editor included. It's bundle fodder, which is where I got it, and the store price is insane. There's nothing really unique here. If you're a speedrunner that has exhausted every other game, you could still find other games with more content. The cutscenes may be longer than the gameplay, but they try too hard to be memetic and get tweets. A hashtag in a cutscene, disgusting. Considering all the levels can be reasonably completed in 240 seconds, you must see the cost-per-hour here is awful. It had potential, but the title restricted the gameplay far too much.