!!!IMPORTANT!!!
It is highly advisable to save all your LP points (gained from hearts, achievement unlocks, and distance traveled) to unlock the second level first. At the second level there are a lot more hearts closer together making it easier to rack up points to unlock bikes and bikers.

Everything listed is achieved with the basic bikes and bikers you start with. 'Bought' bikes and bikers may make achievements easier but they are not required.

Repeat bought bikes and bikers
Personally had issues with 'buying' crates and getting bikes and bikers already unlocked. Unclear if this is a local issue or if multiple players have had this issue. Comments on this would be helpful.

100% Achievement Completionists.
This is not the hardest game to complete, however it can be a boring grind with achievements You love jumps and Drift master.

Jumping
Just hit a ramp. Unclear if it counts as a jump is the boost doesn't activate. (W)

• First jump - First jump
  
• You like jumps - Jump 100 times
  
• You love jumps - Jump 1000 times
  
  
• Two-stage jump - Jump onto a jump ramp
  There are a few spots in the first level this can be achieved. The first is one(1) block down, and one(1) block right. There will be a truck that drives by that could make this problematic, let it pass by before attempting. (W)
  
  
• Back jump - Backward jump
  (Hard drift at the edge of a ramp will usually grab you and launch you backwards. This may take a few attempts.) (W)
  
  
• Truck boarded - Ride on the car
  This is one best left for the second level as there is a prime spot at the start.
  (Rough directions) (W)
  
  • At the start you should see a truck in front of you driving to the right of the screen. This is the truck you will jump on.
    
  • Follow the truck and hit the first ramp, aiming for the above mentioned truck. This may take a few tries as the truck's paths can vary time to time.

Drifting
If you hear the squealing tires, Congrats! You've just drifted.

Using the 'Space Bar (SB)' and the 'A' and 'D' buttons, unclear if holding the 'SB' and pressing 'A' then 'D' and repeating builds them up or if the 'SB' has to be repressed before each direction change. Comments on this would be helpful. (W)

• First Drift - First drift
  
• You like drifts - Drift 100 times
  
• Drift master - Drift 1000 times

Mileage
Just keep driving until the court-martial.

• Mileage 100m - More than 100m mileage in one play
  
• Mileage 300m - More than 300m mileage in one play
  
• Mileage 500m - More than 500m mileage in one play
  
• Mileage 1000m - More than 1000m mileage in one play
  
• Entry rider - Total mileage exceeds 1000m
  
• Beginner rider - Total mileage exceeds 3000m
  
• Intermediate rider - Total mileage exceeds 5000m
  
• Advanced rider - Total mileage exceeds 10000m

Danger Close

• Gas tank explosion - Blown away by gas tank
  
• Drum explosion - Blown away by drums
  
• Huge gas tank explosion - Blown away 100m by gas tank
  
• Huge drum explosion - Blown away 100m by drums
  This one seems to be glitched. Personally unlocked on the second level with a ~10m distance. (W)

Demolition

• You like wooden boxes - 10 wooden boxes blown away
  
• You love wooden boxes - 100 wooden boxes blown away
  Drive into the boxes, it is not required to have them get hit by either the gas tank or drums.
  
  
• Fire hydrant attacked - Fire hydrant exploded
  Run into a placed fire hydrant and have it spring a leak.
  
  
• Truck run over - Run over by car
  Find the nearest tire tread and place your noggin under it.
  
  
• Street lamp broken - Street lamp broken
  
• Street lamp brought down - Street lamp brought down
  Unclear. Possible bad description. Both should pop with the destruction of a lamp. Jumping onto one is the easiest way. (W)

Query-chan found
These bikers are unlocked by finding their respective statues within the two levels NOT thru the crate drops. QueryChan's Statue is found in the first level, while RedQueryChan's Statue is found in the second level. Once you find them a notification will show on the screen and that biker will be unlocked to use.

QueryChan ACHIEVEMENT
She can be found in the back right section of the first level past a few hospitals.

• Directions are in the works.

Keep in mind you will have to do a bit of grinding to remove the rubble piles to get here. Once roughly a third of them are clear you should be able to get to her.

Query-chan found
These bikers are unlocked by finding their respective statues within the two levels NOT thru the crate drops. QueryChan's Statue is found in the first level, while RedQueryChan's Statue is found in the second level. Once you find them a notification will show on the screen and that biker will be unlocked to use.

RedQueryChan NOT AN ACHIEVEMENT
Once you 'buy' the second level, there should be no need to clear any rubble to get to this statue.

• At the start of the second level make the first right.
  
• At the next intersection turn left.
  
• Proceed down the road with three(3) speed boost arrows, a number of hearts, and a ramp at the end.
  
• Hitting this ramp will put you on top of buildings with an opening to the left. Her statue can be found here.

!NOTE!
RedQueryChan; dogs, vehicles and explosions will not knock her off the bike.(Not all bikes tested yet.)

Personally spent over 3 hours grinding out points to unlock QueryChan and RedQueryChan before happening across the Red statue. Hopefully this guide will help you avoid that and not make this same mistake. Thank you for reading/commenting and best of luck!