What are the effects of playing on Easy

It helps to start out on Easy, where you get more scrap and ammo than normal. The only downside is a score hit at the end, but if you're having trouble surviving, score is probably the least of your concerns.

Don't rush things - if you've got time to explore, do so. Don't get caught by the rebels, but don't make a beeline for the jump point, either. This takes practice, but try to make Z or N patterns between nodes as you move closer to the jump point, so that you can hit more as you're on the run. The rebel fleet "resets" in each system, so making more or less jumps in a particular system does not change how fast they will catch up to you in the next.

The other thing that is important is to try to conserve your missiles - you shouldn't be using missile weapons at all in the first system or two, if you can avoid it. Obviously, if it's a choice between death or missiles, use them. Missile weapons pierce shields, so while you can take down shields and do damage with your laser weapons, you should. Shields regenerate quickly, so keep this in mind if you've got multiple laser weapons - you may have to avoid the autofire and target them in volleys to break through shields and do damage.

Try to stockpile scrap for shopping early on if possible. Sometimes your only chance at a really good multi-shot laser weapon will come early on, and this can make or break your game. Beam weapons are far more difficult to use, since they tend to require precision timing - they do the best damage when enemy shields are down. While shopping, make sure you've got sufficient fuel - I tend to like to have about 20 units on hand if possible.

On a similar note, if you can capture ships intact (by killing their crew) you can get the best rewards, including a better chance at new weapons. Destroying oxygen subsystems is a good way to do this early on, although weapons systems tend to be priority targets.

Also pay attention to your crew - keep your crewmembers at the same post and they will gain experience for working that system, which can mean big bonuses. Also, try to protect experienced crewmembers, especially your weapons officer. A maxed out weapons officer is worth his or her weight in scrap! I tend to assign the first person in the list as the pilot, the second as the weapons officer, and the third as the shield operator. That way, I can tell easily if everyone's in position.

Besides getting lucky and finding better weapons, you've also got several alternative options when it comes to combat:

• Get a teleporter, if you've got the crew for it. Having a couple of mantis crewmembers really helps. Wreaking havoc from the inside of the enemy ship is always a plus. Keep your eye on their health, though, as you don't want to let them get killed before you can teleport them back.
• Find a Breach drone and the Drone subsystem. The Breach drone is like the teleporter, except that it sends a robotic drone to the enemy ship, ripping a hole in it and doing damage to crew and systems until it is destroyed. It's quite devastating, and it also pierces shields. There are other useful drones, but this one is by far my favorite.
• Grab the cloaking device. With the cloak, you can charge weapons while avoiding enemy shots.

It's hard to do more than one or two of these strategies at once, because of limited scrap for upgrades, and because it's just hard to manage drones, precision time weapons, keep tabs on your away team, etc, at the same time.

As far as upgrades go, I tend to prefer going for 2 shield units as soon as possible. Then I will focus on weapon system power, and/or system power for one of the optional systems if you've found it. After that, I focus on shields again. Many of the subsystem upgrades (ie, doors, sensors, medbay, oxygen) have less of a benefit compared to extra shields, so keep these at a low priority.

Sometimes, you're just going to do poorly even though you tried your best. Sadly, that's the downside of a "roguelike" type game - sometimes the dice are against you. Don't get discouraged!

I got the "Asphyxation" Achievement twice, once on easy and later on normal.

I don't know about downgrading but you can definitely get achievements twice if you get them the first time on easy and they then get upgraded to normal.

The achievement only shows normal difficulty unlock for upgraded achievements.