Shotgunning and Turtlekaze

This is the easiest shot - point your 'aimer' directly at the enemy and use full power. I recommend using dragshot shooting mode for this, it takes less time than slice. You can switch back to slice afterwards if you want. Unlike a lot of bots, for Turtle it's important to use full power because the shot starts spreading apart as soon as it leaves your cannon. The more power you use, the further the shot goes before it splits.

Because of the way the shotgun spreads, the maximum distance for using it is about 1/4th of a screen. If you try to shoot any further than that, you get a half miss like this:

Turtlekaze

This technique allows you to get maximum damage out of shot 2, but the tradeoff is that you also damage yourself. It's sort of like using the blood powerup, but stronger. To do a turtlekaze you must walk Turtle so that it is almost completely on top of the enemy, use your lowest angle, and tap shot 2. I think a little power is better than 0 power, and I'd avoid using more than a little.

It's best if you can be angled downward a bit, or if the enemy is on a hill, so that you're sort of facing their belly. But it's possible even if you can't get that position.

When you're positioned properly, the shot will start to emerge from Turtle's center (not from his cannon), then immediately explode when it hits the enemy's core. The goal of turtlekaze is to get your shot to hit very deep into the enemy's core, deeper than a normal shotgun or high angle shot can penetrate. You don't want to just get Turtle's red aimer or the blue tip of his cannon the middle. You need to almost be on top of them. If you're not, you don't get the nice damage and you STILL hurt yourself.

When done correctly the damage is huge, 350-400 sometimes. But, Turtle will take at least 200 damage too. So usually this isn't a good tradeoff. There are some situations where it's a smart to use it - for example, at the beginning of the match, let's say the enemy opens with an SS. You may not have the angle for an SS (but you can do turtlekaze). The best you can do is beat their delay with a shot 2. If you do your shot 2 deep in their body, then do a dual shot 2 on your next turn from the same position, you can kill them before they get to shoot again. If didn't turtlekaze and they lived, they would dual you anyway on their next turn and hurt you badly or kill you. So it's better that you do maximum damage to them first. Any time you're definitely going to die on your next turn, you probably should use it.

PS: Be careful you don't try to get so deep inside the enemy that your shot actually misses their core completely. This happens a lot when Turtle's on an upward slope.