How do I get the Striptease achievement/ticket?

Edit: I have found a better song to get this achievement with -- better, because it comes with Beat Hazard itself.

The track is "Beast Mode" by xKore, and is located in your beat hazard folder.

While Badp's answer works for the folks with BOSS RUSH, those folks who want to stick to just the base game of Beat Hazard are in luck: the same pair of boss ships can spawn in normal mode, and on normal difficulty, in a base game without any DLC whatsoever.

It may take a bit of parsing through your library until you find a song with both a "pair boss" spawn and enough time / lack of danger to kite them safely for 1 minute, but it's not outside the realm of possibility. To the best of my knowledge, it is okay to die after stripping both bosses, doing so won't invalidate the achievement (though you do want to make sure that it's not your last life).

In my case, I happened to have Dragonforce's Valley of the Damned handy, which features enough guitar power shredding to keep your guns nice and perky for most of the song. Disciples of Babylon was the song that ultimately got me the achievement, though, like most Dragonforce songs, it is a little on the long side.

The point to take away from this is that it's totally possible to earn this achievement in normal gameplay - experiment with your library, you might find an even better song!

If you have the Ultra DLC, this is a pretty simple recipe to get the ticket relatively easily.

1. Download the Songs to Test By, Volume One album from the official site.

2. Extract the song "15 acres of Broken Glass."

3. Play it in Beat Hazard Ultra in Boss Rush mode.

4. Wave 1 will be the two mini-bosses you'll need to strip down. Simply aim at their guns and circle around them; be careful about their lazers. The song is very slow and the wave timer adjusts accordingly. Wait for wave 2.

   

5. Wave 2 will be a larger boss coming from the bottom left hand corner. Fire at it being very careful to not hit the other two bosses. The superbomb is safe to use if the 2nd wave boss completely covers your two naked bosses. Just survive.

6. One minute later, celebrate your achievement!

   

If you have the Ultra DLC you can easily get the achievement in the following way.

In Boss Rush mode play the song Trancemission - Johnny Frizz included in the game: two bosses spawn immediately, just destroy their turrets fast and then stay in a corner and try only to avoid missiles of 3rd boss that will come after the first two.

If you have problem try to buy a couple of perks, the one that give you 2 more lifes and the one that give you already some power-up at start.

All credits goes to JRTF2 that posted the solution on Steam forums and published this video: