Estimated achievement difficulty: 2/10
Offline: 20 
Online: 0 
Approximate time: 5 Hours
Minimum number of playthroughs needed: 1+ playthrough
Missable achievements: No [Level Select]
Does difficulty affect Achievements: No Difficulties
Unobtainable/glitched Achievements: No
Extra equipment needed?: No
Is there DLC? No
LocoCycle is an action game by Twisted Pixel where you play as a motorcycle who is dragging her mechanic behind her. IRIS (the motorcycle) wants to go to the Freedom Rally, but Big Arms, the company that payed to manufacture her is trying to get her back or destroy her.
I would upgrade in this order:
Don't be afraid to use all your points after every level, doing so will allow you to do better in later levels, which will allow you to earn more points per level.
The reason I recommend upgrading in this order is because you will be able to fully upgrade your melee ability before reaching level 5-2 and will be able to get "Champion Streaker"
without having to replay the level and not having your weapons upgraded doesn't seem to affect your ranking.
Step 1 Story
Just play through all the levels. You don't have to worry about getting A Ranks on the levels. It is not required for any of the achievements and I'm not sure that it is even possible on a few of them until IRIS is upgraded. However, the better you do the more points you will have for upgrades and extras and the less replay you will have to do. This will get you most of the achievements in the game.
Step 2 Garage
Now from the main menu go to the garage. You should have enough points to purchase everything here so do that now. This will get you "Big Movie Watchings", "All Game Secrets Revealed", and "Behind the Scenes Bonus DVD". If you don't have enough points to purchase everything go back to a level you did poorly on the first time through and with IRIS fully upgraded you should be able to do much better. The reason you want to replay a level you did poorly in is because of the way points work. When you replay a level you get the points you earned minus the points you earned previously so if you play a level you did well on you will get very little out of it.
Step 3 Mop-Up
Finish off any of the random achievements you have left. Most of these can be done on level 1-1. "Pablo Thanks You"can be easily done on level 1-3. "Champion Streaker"will need to be done on level 5-2.
LocoCycle is an interesting and decently fun game. You will have another 1000 before you know it!