Radial Defender Strategy: Triage, Shot Timing and Surviving Late Waves

Updated October 2026

In Radial Defender you guard the rim of a circle split into ten spokes while enemies crawl outward from the small ring in the middle. You never aim and never press fire; the ship shoots by itself. Your only decision is which spoke to stand on, and when to leave it. That sounds simple, but by the mid-game enemies arrive faster than you could ever kill them one spoke at a time. This guide explains exactly how firing, movement and the waves work, then turns those numbers into a way of moving that keeps every enemy short of the rim.

How your ship moves and shoots

Tapping the left half of the play area steps the ship one spoke counter-clockwise; tapping the right half steps it one spoke clockwise. Holding a finger down repeats the step every 0.13 seconds, and sliding the held finger across the middle reverses direction almost at once. With ten spokes, no spoke is ever more than five steps away.

The ship fires one bullet every 0.22 seconds, always down the spoke it is standing on at that instant, and it keeps firing while you move. Bullets fly inward fast enough to cross from the rim to the inner ring in a little under half a second. Each bullet destroys the first enemy it meets on its spoke and then disappears, and a bullet counts as meeting an enemy when the two are within 14 pixels of each other along the spoke. That window is wide compared with how far either moves in one frame, so shots do not slip past their targets.

The most useful fact here is that a bullet keeps its spoke after you leave. Once a shot is on its way toward an enemy, that enemy is dead even if you step away immediately. You do not have to stay on a spoke until the enemy pops; you only have to be there long enough for one shot to leave.

How the waves grow

Each wave sends a fixed number of enemies, one at a time, on random spokes. Three things scale with the wave number, and none of them ever stops:

• Enemies per wave: 8 on wave 1 and two more every wave after that, so 26 on wave 10, 40 on wave 17 and 46 on wave 20.
• Time between spawns: 1.2 seconds on wave 1, 0.075 seconds shorter each wave until 0.525 seconds on wave 10, then 12 percent shorter every wave with no lower limit: about 0.36 seconds on wave 13, 0.22 seconds on wave 17 and 0.15 seconds on wave 20.
• Crawl speed: an enemy needs about 10 seconds to reach the rim on wave 1, about 7 seconds on wave 5, about 5 seconds on wave 10, about 4.1 seconds on wave 14 and about 3.2 seconds on wave 20, and it keeps getting shorter.

The first ten waves ramp up gently, and after that every wave is harder than the last. There is no plateau to settle into, so each run ends eventually; the question is only how far you get before the waves outrun you.

Kills are worth 10 points and each cleared wave adds 100. A wave counts as cleared when its last enemy has spawned and every enemy on the board is gone, and the next one begins spawning after a short pause.

The arithmetic of survival

One shot every 0.22 seconds means the ship can destroy at most about four and a half enemies per second. Enemies arrive at about 1.9 per second on wave 10 and 3.6 per second on wave 15, so you still have some spare firepower there, but not much, and every step you take between spokes is time when your shots may land on empty spokes. From wave 17, enemies spawn faster than one every 0.22 seconds, which is faster than even perfect shooting can keep up with, so the run ends within a few waves.

That is why the order you visit spokes matters. To test it, we ran a simple strategy in our simulation of the game's rules: always head for the enemy closest to the rim, one step at a time. Stepping every 0.13 seconds, which is the hold-repeat speed, it lasted about four minutes and fell on wave 18 to 20. Even a version that could step once every frame got no further than wave 22. Slowed to one step every 0.25 seconds, it fell between wave 15 and wave 18. Quick, purposeful movement is what decides how far you get.

Triage: who to shoot next

1. The outermost enemy comes first. Whatever spoke it is on, the enemy nearest the rim is the one that will cost a life. Head for it by the shorter direction.
2. Shoot on the way. Because you keep firing while stepping, holding toward a far spoke drops bullets on spokes you cross. If an enemy sits on a spoke along your path, a brief pause there is often enough to send a shot.
3. One shot, then move. Once a bullet is on its way, leave. Staying put only makes sense when a second enemy is stacked further in on the same spoke.
4. Let newcomers wait. A fresh enemy near the centre has several seconds of travel ahead of it, even in late waves. Clear the outer ring first and catch the inner ones on the next pass.
5. Watch for stacks. Two or three enemies on one spoke need two or three shots, which means standing still for half a second or more. Spot them early so you are not forced to camp there at the last moment.

When a life is lost

When an enemy reaches the rim you lose one of your three lives, the screen shakes, and every enemy in the outer part of the ring (beyond 78 percent of the rim's radius) is removed. Then the action freezes for 0.6 seconds: enemies stop, nothing spawns and your ship stops firing. Taps still move the ship during the freeze, so use the pause to look over the board and step toward your first target, because the next closest enemies are now the ones you were ignoring. Players often lose a second life right after the first because they restart in panic toward the wrong spoke.

Enemies swept away by a lost life still count toward the wave, so the wave can still be cleared normally.

Practical habits

• Keep two thumbs ready. One on each half of the screen lets you reverse direction without moving your hand.
• Count steps, do not aim. Tapping where an enemy is drawn does nothing special; only the half of the screen matters. Decide "three steps clockwise" and tap three times.
• Use the hold for long trips. Four or five steps are quicker held than tapped for most players.
• Rotating your phone mid-run is safe. The circle is resized to fit the new screen shape, and every enemy keeps its place along its spoke, so nothing jumps past the rim.
• Finish before you look away. The game pauses its motion while the tab is hidden, but it is easy to lose track of the board when you come back.

Your best score is stored on your device, and any score above zero can be saved to the Hall of Fame from the game-over card. Practise the first ten waves until moving toward the outermost enemy becomes automatic; after that, every wave asks for a slightly faster rhythm than the one before.