I haven't in the newest build yet, but I've been busy writing blog posts. :P
If you got there, tell us what your strategy is!
What upgrades did you get? How do you avoid death??

Human! You are about to become a sword robot! · By
I finally got to titanium, started with arrow block then tried to max out bow(to kill Spider Tron 6000) and made sure I had at least 1 clone at round 7 and 2 clones after round 13. for the most part I just kept moving killing whatever I could focusing mainly on archers and spidertrons. the jetpacks seem to be weak to walls and edges so I kind of exploited that to kill them. I died at round 16 :( \
update: got to level 17 mainly kiting large enemy force around while there archers/ spider bots friendly farm them then slowly eliminating spider bots and archers until only the main groups remain then I just slaughter them.
GOT TO ROUND 20
My highest score is 17 (so far), and my upgrades were as below:
1. Block Arrows I
2. Block Arrows II
3. Block Arrows III
4. Jetpack
5. Energy Capacity I
6. Clone (hereafter, if I die in a round, I will temporarily halt upgrading to create another clone)
7. Energy Capacity II
8. Energy Recharge I
9. Bow
10. Arrow Width I or Energy Recharge II
Energy Recharge II (or Energy Capacity III if already taken)
I mostly use the jetpack for getting away from hordes, trying to get some wiggle room to take out Spider-trons. I find that using it for offense, especially in later rounds, will often leave you completely exposed in the middle of a horde. RIP.
So that's my strategy, anyway. I think the fatal weakness of my plan is relying too much on being able to redirect arrows. When I swing my sword to attack something, much less turn my back to an archer, I'm left wide open.
First all the arrow block upgrades.
Then a clone. (if you die, get a new clone before continuing.)
Then both kick upgrades so that you can get up if spider-tron knocks you into the sawblades path.
Then jetpack
Then jetpack 2, full energy capacity and energy recharge in no particular order.
Then upgrade the rest however you want.
I got to level 14 (First Titanium round, then I got mowed by MK2 Jetpack Drones) like this:
1.Kick
2.Get up!
3.Block Arrows I
4.Clone
5.Jetpack
6.Jetpack II
7.Energy Capacity I
8.Clone
9.Block Arrows II
10.Clone
11.Energy Capacity II
12.Clone
13.Energy Capacity III
Then, I didn't pass round 14 because of stupid MK2 Jetpack Drones.
Yo guys is this the highest anyone has ever made it to? https://gyazo.com/d7b3a156425f279c8df8593160e66a72
Took so long to do but I think it was worth it.
Block arrows first - ALWAYS!
Kick/Get Up somewhere in silver tier,
Jetpack in Gold Tier (Jetpack 2 in Titanium, because I want to at least get the same speed as the mk 2 jetpackers for my playstyle)
With the exceptions above, I prioritize Unbalance/Good Form, because I use my sword a lot, even against the Mark 3 combat archers (just block their bullets and hope for the best, usually :P)
My only problem is the Spider-trons, especially 6000. Requires a bit of effort with just swords to cut them down to size.
And look where it got me!