Hard badge: Max engine, wheels, transmission and rest on fuel. Save fuel by sliding down first hill and flat without accelerating. Day 2. Max fuel, rest on gun+ammo. Day 3. All on boost, boost final slope to fly over barrels.
21 Day Story mode: Wheel 2, Fuel, Engine 2, Fuel, Wheel 3, Transmission 2, Max Fuel, Engine 3, Fuel if not maxed, Transmission 3, Optional Boosts. Save for 2nd vehicle, you should be making $25K/day, so 2 days.
Day 9: 2nd vehicle, Engine 2, Fuel, Transmission 2, Max Fuel, Engine 3. You should be making $40-70K, start saving for next vehicle, it doesn't matter if it takes 4-5 days, as long as you get it ASAP.
Day 17: Final vehicle, get Engine 2, Transmission 2, Fuel, Wheels 2, Rest in Fuel, Engine 3, Max Fuel. Then get Max Boost and Gun, don't bother getting Transmission 3. Boost at the first crates to get a lot of 120 mph airtime, and then you should still have enough fuel to boost any time you slow down. You should be able to finish the game this way.
Wave 300, everything is going well, a Colonel, 10 Heroed NCOs with BARs. Wave 317 Unfair Event: (precision) V1 Blitz. I lost 3 Bunkers and all of my backrow, apart from 2 NCO Snipers. A game never went to shit so fast.
Wave 400+ doing well with my 6 man squad in a centre bunker and then.. bottomburgers- we couldn't kill them fast enough R.I.P. ~Wave 200 we survived around 15 airstrikes/V1s in a row, trying to get 10 TP to replace 2 CamNets, the aerial support just kept coming until it was up.
6 days completion. Upgraded Bullets for $20, then Money as much as possible with 1 Magnet upgrade. Then Bullets & Fire Rate evenly. Then 1-2 Movement to collect coins and dodge easier, rest in Health. Finished off by maxing Magnet and Movement.
I got a 100 Rifle Sergeant Gunner, yay. Then.. Wespe Blitz, V1 Blitz, and Brandenburg Blitz all together 1 wave apart each. Okay, I did something wrong or the game hates me. Brandenburgs finished off my remaining troops :P
Tips to not get stuck at Danger 10:
1. Get Support Call 1 and 2 asap, 3x Support Call 2 is a monster.
2. If in doubt, pick combat upgrades over grabber and fuel.
3. If in doubt, never upgrade missile launcher & upgrade rifle when you can.
4. You'll quickly get to the point where you only need 1 fuel, put it at the back where it's safest (with the cockpit).
5. 24-36 collect (4-6 lvl1 grabbers) should be enough, you can always sell them to fortify the ship.
6. Shields suck to start with, as the range is small and they don't prevent boss melee attacks.
Every level from 10-20 can be done the same way. Attack an entity with 2 or more of yours, cut tentacles prematurely to transfer armies faster between yours and enemies, works best on your own colonies.
zone 10: The trick is red is slower on the uptake even though he has a larger army. Attack 2 of his areas with 2 of yours each, your 40 will beat his 30, and then you can focus on defending 6 zones vs his 2.
Starting to get frustrated with Agile Red, the number of times you hit a fireball 0.5 seconds after starting (immediately on drop) before vision even starts to return (can tell from the collision noise)
edit: got it on the run after this comment, finally, took that long not to hit a fireball on drop :P
For the love of whichever deity, enable the $ gain as soon as you can click on confirm for watching the ad. The broken ads amount to millions of lost $ which really slows the game down, at least half of the money you get comes from ads. I've had 5 broken ads in a row now, refreshing doesn't fix them.
Badge in less than 25 days (my fastest 16 days): get kick and trainers, then anything that extends distance, like milk, oil, cars, birds, hydrants, umbrellas, balloons and especially dogs. Anti-poo doesn't remove poo so probably reduces its stickiness. Evolution is good with maxed birds.
It doesn't really matter how fast you travel because extending distance matters the most. The money boosters don't give much for their cost. When you're hitting 30K+ it's a good idea to save up for double kick (50K). Chinese sandals should be good too if you skip Skates, although you don't need them to hit 1M.