Before I get into this, I want to explain the 3 game modes that Arkanoid DS has: Clear Game, Uranoid, and Quest Game.
Clear Game is a standard 35 round game. You play 7 zones of 5 rounds each. After clearing a zone, it branches out to 2 more zones. This means that there are 64 possible routes. After clearing the final zone, you rescue an alien (Zones Z', V, W, X, Y, Z, & V' all have one). The credits play after finishing a Clear Game, so you could consider this to be an ending for TASing purposes.
Uranoid is unlocked after rescuing all 7 aliens. 7 zones, but it's a linear path that only splits to 3 zones after the penultimate zone. You could consider the "true ending" of this game to be rescuing all 7 aliens and unlocking Uranoid. The credits also play after beating Uranoid too.
Quest Game is basically a mission mode. Every mission is unlocked by clearing it in Clear Game/Uranoid. Finally, there's also a shop to buy extra stuff using Reward Points you gain from playing. So if you really, really, really want to, you could make a "100%" TAS where you play every level & unlock everything. This would require 47 050 Reward Points (which requires 14 115 000 total points). I only get 1/49th of that in this movie, so, yikes. But honestly, I wouldn't mind trying to do this if I had the time. Alternatively, you could just have a "Quest Game" TAS where you start from a sram, which probably sounds the best.
Anyway, onto the actual TAS.
I chose Hard difficulty because it makes the Energy Ball accelerate and move faster. Clearing a zone without having your barrier touched gives you bonus points depending on what you set your barrier to. Barrier of 1 is 3 000 points. Barrier of 0 is 5 000 points. If you have a barrier of 1, but get it touched, it'll skip the bonus point tally at the end, which is roughly 23 frames faster than having a point tally. However, I used a barrier of 0 because I believed that that timesave would be negated by the extra distance the ball needs to travel to hit the barrier (and because I thought it would be more entertaining). I went with stylus controls because they basically let you move the Vaus instantaneously.
Initially, I was going to TAS all paths and pick whichever was the fastest, but I simply just lost motivation on this. That's why you see me choosing the left branch all the time. I don't know how RNG works in this game, and the closest I was able to manipulate it seemed to be based on whether or not I picked up a power-up capsule or not. I mostly went with Laser (L), Disruption (D), & Megaball (M) but sometimes I went with Catch (C). I almost always avoid Slow (S) and Reduction (R) because they're absolutely useless. I did pick up Slow a few times however, because I could then grab a better power-up later. Warp capsules that allow you to skip zones do exist in this game, but they're rare. If you could find a way to manipulate RNG, you could just grab a warp and skip most zones.
I didn't use any tools, and I'm not really proud of my work. But I figured I'd upload this anyway just so that there's something to compare to in case someone else decides TASing this. Besides, I guess it's not all a waste.