For this year's Halloween Riot decided to make big changes to Twisted Treeline (3v3) map and few other things. They made new 3 versus 3 map called Shadow Isle with lots of new fun and content.
Everything with the new map has changed. It still has familiar lane setup with two lanes but without jungle on the top side of a map, apart from one big epic boss monster called Vilemaw. The jungle is now fully focused on the center of the map. The base has been also changed so that players can't turtle up so well anymore which was the problem in the old Twisted Treeline. Players who were losing just kept pulling minions to spawn point where fountain lasers kept destroying one by one which disallowed enemy team to destroy the nexus and finish the game.
The jungle changes are huge. Before it was quite hard to jungle and only a selected few champions could jungle well. Killing double golems was nearly impossible at level 1 without smite, same goes with wraiths because big wraith was healing for too much. The camps were also randomly generated which meant that sometimes you could jungle well sometimes not.
Now it is rather easy to jungle and you can do it with almost every champion without even needing the smite (if you have tier 3 runes). Some people prefer to take smite to secure Vilemaw kill. Each side has three camps now, wolf camp, wraiths and double golems. Riot scaled their strenght down little bit so they are easier to kill. Junglers can now keep in levels and experience with lanes quite well.
Another new feature is the altar system. There are two altars, one on each side and players can capture them after they unlock 2 minutes after the game starts by standing on them for a short amount of time.Have an altar captured it gives an entire team +4 bonus gold on champions and minions kill. Because most of the time one team will have one altar and the other team other one it evens out. While team with two altars captured will not only deny that bonus gold to opposing team, they will also have extra 10% AP and AD. After the altar has been captured it's locked for next 90 seconds and it gives you the vision around it. Since there are no wards, the vision is really important because it could prevent some ganks. There is also one movement speed shrine in the center of the map which gives you some movement speed for short amount of time and also you will become visible on the map.
Dragon has been replaced with new epic boss Vilemaw, a huge spider with new AOE abilities. One of them is that it pulls all nearby players to it and it also has stacking armour and magic resist debuff which makes tanking really hard.
In addition Riot is introducing new skin wards which are available to purchase in shop and will last for certain amount of period. You can either purchase them with RP or IP. Also they are giving new summoner icons to RP spenders, to encourage players to spend more money.
