Campaign Pace
The schedule of UFOs, aliens, research and disassembly, as well as the tech tree itself, has been changed significantly. Over the course of the campaign, the player will face fewer UFOs and this will be most apparent at the start of the game. It may lead to the start feeling "empty" of UFOs for those who are used to the excessive UFOs seen in 2.4. The pace will increase before long. There should be no large chunks of time with nothing to do like 2.4, and you had better get moving quickly on research and development.
While I greatly enjoy the new slower rate of encounters (perhaps I can actually get to the later stages of the game now!), the beginning is a bit too barren. I was able to research all techs by the end of the first month or so, and waited a whole 'nother month before any new research items became available. Similarly I have nothing to fight, and I cannot make any money (because there are no alien ships/weapons to sell) All my soldiers, scientists and workers were idle for almost a whole month. After that however the game picked up nicely, I am still in the first year so we'll see how it ends up later on.
Air Combat
The aircraft vs. UFO balance has been adjusted quite a bit. Be careful making assumptions based on your previous experience.
I haven't noticed any significant change to the air combat. My fighters still take out alien fighters and scouts, and not even two simultaneous fighters can take on a harvester.
Laser Weapons
Handheld laser weapons are no longer available as soon as you research CWS at the start of the game. They will come later. This may be particularly disorienting for our long-term players.
I never went for the early laser weapons (gl/sniper/flamer worked for any occasion typically) but sometimes went for the rail gun. I don't mind so much that laser weapons were moved, but so were the rail guns. As I mentioned before in the beginning months there is nothing to do -- there should be some sort of weapon upgrade that I can research early on because I'm still stuck at the basic weapons many months in to the campaign.
Ground Combat Difficulty
Expect to face more aliens who are more difficult to kill. In general, you will likely find your soldiers dying more. You will also receive more recruits throughout the game to allow you to suffer more casualties. Do not expect to be able to play a zero-casualties game as easily as before.
Bwahaha, this is spot on.
Weapons
The weapons have been comprehensively re-balanced and have undergone significant changes. In general, weapons have been adjusted to better serve specific tactical purposes. That means the trade-offs between different weapons and different firemodes within weapons are more significant now. Without getting into specifics, I'll just say that you should pay special attention to all of a weapon's attributes and think about which tactical situations it might be most effective.
I never really liked the balance of weapons in UFO:AI for various reasons, but some of the weapons seem to be completely redundant or useless, especially with the new RF system. Is there a wiki page or something that shows each weapon's tactical purpose? I should probably gather my thoughts and put these in a new thread...
Wounds and Healing
The game now includes a proper wounding and healing mechanism. Soldiers will get wounded and bleed out each turn based on how wounded they are. A medikit is able to heal wounds, which will stop bleeding, but it will only be able to give a soldier back a very small amount of health. Soldiers are expected to recover in Hospital. Medikits are for keeping them alive until the battle ends.
The medkit now has three options: antipsychotics, stimulants, and first aid. I kinda guessed that antipsychotics cured morale (never tried it though, as morale never got low enough) and first aid healed somehow??? but there is no information regarding what does what. I have no idea what stimulants do and my soldiers still bleed out and die even if I give them first aid. Do I have to continually give first aid during the duration of the battle? I'm not sure I like that. I think its great that medkits have been made more realistic (there were times when I wouldn't kill the last alien because I had to heal up my wounded soldiers before flying home) but medkits may need a small buff, especially in conjunction with the tougher aliens.
Weight and Encumbrance
All soldier items now include a weight and soldiers can only carry as much as their Strength ability allows them. A soldier will be "encumbered" and will lose TUs when they are carrying more than 50% of their max weight. A soldier will be "light" and gain extra TUs when they are carrying less than 20% of their max weight.
This makes the backpack storage completely useless. TU's are penalized *way* too heavily (how does weight affect TU's anyhow? it would be nice to have a bar showing troop TU next to their weight) Heavy weapons should be heavier (and appropriately more powerful) to compensate for a TU penalty buff. I personally would also loosen the thresholds to 60% heavy, 30% light on top of TU penalty buff (or even 66/33 to make it nice and symmetric)
Anyway, its a good first start
Soldiers Stay Equipped
Soldiers will now stay equipped when they are not assigned to a dropship and can be equipped through the employees menu.
WOoO! Love that I can finally equip my guys off the plane. This is a huge awesome change.
More Soldiers
You can now have up to 12 soldiers on the battlescape. The starting dropship, the Firebird, still only supports 8 soldiers, but base defense missions and later dropships will support more.
I haven't gotten to the point when I can ship out 12 soldiers at once, but I like it nonetheless. I have had a few base defense missions, but I never have more than 8 guys in a base at one time. Something that struck me as odd though was small hangers no longer let baddies in, but workshops now do. Why was this changed? To shake up veteran UFO:AI players? After the first go around players will just optimize their bases differently to increase the alien funneling. Perhaps the entrances should be randomized so not all the time workshops or hangers etc. will be open to alien invasions. I also noticed cameras, but they didn't grant me vision
And I still don't have base auto-turrets... but I'm a little off topic now.
New Weapons
New weapons and equipment have been introduced for soldiers and aircraft. Most of these become available late in the game.
Haven't noticed anything yet. Heck, my selection of weapons and equipment has been severely limited thus far, but the game is still fun. How far in (eg. how many missions will I have to fight through) to get to the late game goodies?