Star Raiders
12 Achievements
Arms Dealer
Buy all of the weapon upgrades and android co-pilots
6.5%
How to unlock the Arms Dealer achievement in Star Raiders - Definitive Guide
PeaceSquid
TrueAchievements
TrueAchievements
This is missable and you're not guaranteed enough credits to buy everything so make a point of destroying everything. Because this game was developed by fucking idiots, you may not realise that you have to press Y after missions to get back to your actual base where you can buy upgrades.
Milk each level for those mini-asteroids (worth 50 salvage credits each) and make sure you get all the fuel cells on level 7A (they are worth 300 each). If you do this you'll have enough credits by mission 8A.
Take down fighters, cruisers and frigates that aren't part of your mission objectives for extra credits.
The final upgrade is given to you for free during mission 9A when you collect the android 'Brain'. The achv will pop there and then if you've bought everything else.
The Globalizer
TrueAchievements
TrueAchievements
I generally recommend doing a little bit of farming of salvage early in the game, as it helps with the difficulty. Shooting rocks can be a bit tedious, however, so don't worry about not earning enough salvage, as there is a great place to farm salvage in Sector 5A:
Make your way through the mission until you're tasked with opening the containers to find Rapture parts. Clear all enemies. You'll notice that three Advanced Fighters will spawn at a fixed location every time you clear the level. Camp that spawn in Turret Mode using your (hopefully, fully-upgraded) guns; ideally, you'll be about 2km away, in the path they fly after spawning. They will spawn forever, and each kill will net you 350 salvage credits. I ended up with about 73,000 salvage credits and over 200 kills in this level.
It takes about 130,000 salvage credits to buy all upgrades. I earned over 224,000 salvage credits in my playthrough, so the farming wasn't necessary, but the fully-upgraded weapons certainly helped.
Great tips! Just wanted to add that you can just "remain in zone" on Sector 5A and the enemies will spawn infinitely even then.
Vyrastas
You buy weapon upgrades or android co-op pilots on the Solaris, which is your home base. To return to the Solaris during a mission, press 
and then 
- this will quit the mission and return you to the galactic map, stats and upgrade screens. You also have the option to buy stuff between missions.
To get this trophy you need to buy all 32 upgrades and androids, plus rescue the Brain android at the end of Mission 9A. If you buy everything before Mission 9A, the trophy won't pop until after you rescue Brain.
You buy things with salvage credits, which you get by destroying enemies or little asteroids that float around space during each mission. You will need about 128,000 credits to purchase everything, but don't fret, once you get to Sector 4 and beyond, credits come easier, so it's very easy to get this with just a little farming.
Don't spend time shooting all the little 50 credit asteroids before leaving an area, it's a waste of time. Play through the game and do your farming in Mission 5A. Stay in that sector after completing the main objectives (press 
to remain when you get the "mission complete" screen). Three Zylon advanced fighters will continuously spawn and circle the large space station. Stay in Turret Mode and take them out when they circle near you. They give 350 credits each, so with this method you can get 1,050 credits every 10 seconds or so. Quick and easy cash... stay there until you have enough credits to get all the upgrades and androids. Shouldn't take more than 15-20 minutes.
Another good area to get a lot of credits is Mission 7A, where the asteroids are blue and are "fuel" you must destroy as part of the mission objectives. These will give you 300 credits per, so destroy all of those if you still need credits by then.