Pixel Gladiator

After much trial and error, here is what I did to get this achievement wave by wave -- as well as some tips.

Tips
- Once the bats and whales/sharks start spawning, focus on these first. Use the rocket boots to continuously move and shoot them constantly. The fireballs will continue to cluster and your turrets will help eliminate most while you're moving around
- Use the platforms to get the fireballs clustered together and chasing you, then drop down or boost up and to the opposite side for them to change directions and head straight at you. This helps to make the most of each reload
- Stick to the auto rifle the entire game
- In between waves, practice using the rocket boots if you're not great at using them. I often went in kindof a [_____] shape. Dropping from the far side, hovering under the platforms and coming up on the far side to land. Note: Make sure you're ready to hit boost when you drop off. You don't want to drop like a sack of potatoes then use all of your boost climbing back up
- Lastly, don't hold the boost button. Continually tap to boost and allow it to regenerate.

Wave-by-wave
Wave 1 - Purchase the Rocket Boots and Auto Rifle
Wave 2-3 - Save $
Wave 4 - Add Extra Life and drone
Wave 5-9 - Add as many turrets as you can; continuing to move and focus on the whales
Wave 10 - The boss will continue to move in one direction, so rest on the furthest platform, fire the entire time he's coming towards you, then use the boots to move and dodge. I continued to use the auto rifle for shooting from afar. The grenade launcher kept me in poor spots and I ended up (a) not doing damage until he got close, (b) taking more damage because I was often slow getting out of the way

Please leave a comment before downvoting. Happy to answer any questions.

Beat Arena 2. Video guide here (19:30):

ROCKET BOOTS are essential for ARENA II and you’ll need them if you want to pass this one. Therefore, I’d recommend the boots are your first purchase.

Next you should focus on gathering enough money to buy the AUTO-TURRETS. Turrets will cost: 1. 500$, 2. 1500$, 3. 2500$, 4. 3500$. The prices increase by 1000$ with each purchase, the buying order doesn’t matter.

Starting with top AUTO-TURRETS, I focused on getting all turrets on one side before moving on to the next (I started on the left side). I didn’t buy any weapons, except for the RIFLE in later waves as an option to shoot from the distance whilst hovering.

In the first couple of waves, it’s enough to move little as enemies will come to you. Use your pistol’s secondary weapon feature to kill the enemies easily. Dodge the exploding bats if necessary.

Once more enemies spawn – including the whales – you will need to move more. Hover from platform to platform and allow the turrets to deal some damage. Every now and then use the pistol and get some multikills, as the enemies will line up perfectly. Whilst not necessary in the first couple of waves be sure to buy the HEALTH UPGRADE.

Wave 9 should give you enough money to buy either the GRENADE LAUNCHER or PLAZMAGUN – you need one of those for the BOSS FIGHT. I went for the LAUNCHER and finished off the level.

The Boss has simple move-pattern: he will charge you, once you evade, he will charge you again. However, as the boss moves with slow speed dodging and evading is not too difficult. He is shooting exploding missiles which rarely hit me.