- Estimated achievement difficulty: 7/10 [Achievement Difficulty Rating]
- Offline: 10 
- Online: 2 
- Approximate amount of time to 1000: 3-4+ hours [Estimated Time to 100%]
- Minimum number of playthroughs needed: 3, one of each mode
- Missable achievements: None [arcade style gameplay]
- Does difficulty affect achievements: No, can lower difficulty in Original mode
- Unobtainable/glitched achievements: None
- Extra equipment needed: None
Pulstar is a side-scrolling autoscroller shoot-em-up game where you pilot a ship and shoot your way through various enemy ships and creatures attacking you. Along the way you can collect various types of power-ups for your ship to make things easier (relatively). For the achievements, this game unfortunately resets your score in Original mode if you use a credit to continue, so you'll need to heavily abuse the Create Interrupt Save to make it through Original Mode. After that, expect to put in a ton of practice to get the necessary scores in Caravan mode and especially Hi Score Mode.
Step 1: Original Mode
As noted in the intro, this game does not retain your score if you lose all your lives and have to continue. Because of this, make sure you definitely go into game settings to increase your lives to max and lower the difficulty to 1. Then make sure to abuse the Create Interrupt Save as you go. Refer to the "Score 600,000 points" achievement solution for more information. Once you reach 600,000 points, let yourself die until you run out of lives, don't continue, then post your high score. That'll get you 5 achievements for 400.
Step 2: Caravan Mode
I recommend doing Caravan Mode second because the scores are lower and more manageable than Hi Score Mode. For these achievements, you're going to need to beat the first level without dying and then progress a little way into the second level to reach 120,000 points. This will definitely take some practice to get used to the first level and learn it, but you'll absolutely need it for the next step.
Step 3: Hi Score Mode
This is the toughest part of this game. Reaching 200,000 points is going to require you to finish the first two levels without dying. The first level will eventually become a piece of cake, but the second level has some very bullet-hell parts to it that can drive you crazy. There is no way around it: you're going to need to practice both levels a lot unless you get really lucky. Once you beat the second level's boss without dying that should put you over the 200,000 point threshold. Let yourself die and upload your score to get your last achievements.
Pulstar is a pretty generic shoot-em-up game with some very difficult scores and tough gameplay. Getting the last Hi Score Mode achievement will really test your patience. But if you managed it, congrats on a very well-earned completion.
[XBA would like to thank Necrophage33 for this Roadmap]