I did find that taking out too many of the bigger enemies made it too easy for the AI to defend the base and it I wasn't making much progress when that happened. You can probably take some out to extend the length of the round and get more repair points. This is easier to do in the earlier rounds before the trolls and stuff start showing up. Once it hits like 10-20% damage I race over to the top of the hill next to the bunker and park next to it and repair the base. I just kind of sit there there and let the AI and enemies fight it out while watching the map and staying away from the major groups of enemies. Once the round starts I drive to the cave refuel circle. But if you die during the round you will need to re-pick them up. But while working your way to the 4th or 5th round, make sure you pick up all the weapons so that your checkpoint already has them. This causes more and quicker damage to the bunker you are protecting. But when you get to 4 or 6 fail the round and switch the difficulty to the highest level you can. You can get this far on easy if you want. So you can load up the xbox dash achievements and track your % progress that way. I know I did 7% before, and maybe once I did 10%? And considering you need 10,000 points, those %'s are not too bad. I my average is probably 5% per game but more is possible.
![gas guzzlers extreme sli gas guzzlers extreme sli](https://images.gamewatcherstatic.com/screenshot/image/2/a1/138982/107344847.jpg)
![gas guzzlers extreme sli gas guzzlers extreme sli](https://cdn.cloudflare.steamstatic.com/steam/apps/277820/ss_2022d7f6281cd100c1e1b009633caeb728349ceb.1920x1080.jpg)
I do get decent chunks of % on the achievement tracker. Though I don't really get many kills doing this. I feel like I have a decent strategy for this.