Fissure creep stacking
Oh boy, that was literal cancer. For many years offlane was the hardest lane to stay at. Back to The International 2011/2012 days, it was fine to have only level 2 at 5th minute as an offlaner. As time moved on, players tried to come up with many different tricks to ease the process of laning in the offlane. Some teams would pick Lich or Enigma to deny allied creeps and give some farm to the offlaner. Some players started to Toss allied creeps on top of cliffs. In the current meta, we have offlaners moving behind the enemy tier-1 tower and stealing the creep wave.
However, the dirtiest thing ever created by Dota 2 players was creep stacking with a fissure. Earthshaker would cut some trees and create space inside them. Then he would use the fissure to make creeps run into that space and then block them off with his body. It allowed Earthshaker to stack an insane amount of creeps, which meant that his offlaner would get free experience and huge level advantage. Later Earthshaker would let creeps out, and with the level advantage of his offlaner they would immediately destroy tier-1 and tier-2 towers. Sometimes they would even kill barracks.
Level 1 Roshan
This one hurts the most. So many good memories come to mind when you think of level 1 Roshan attempts. The ability to kill Roshan at level 1 created so many opportunities for teams, very sad that this is no longer the case. Alliance was the team that abused Roshan to its maximum. They would enter Roshan pit with smokes, they would use 5 teleports to get to Roshan pit faster, they would even bait their opponents to assume they are roshing.
Sadly, in the current patch Roshan gives way too little experience. Back in the days, you used to get level 2 immediately after killing Roshan. Not on one hero, on the whole team. Now you can’t get level 2 even if you kill it with only one teammate. Not to mention, you no longer have the ability to use Town Portal Scroll at the beginning of the game.
We really hope that Valve is going to implement some changes to Roshan in near future.
Level 1 Tower siege
Technically, this trick is still available but used very rarely. Now that Dota 2 has become a lot more serious players no longer try to make crazy plays. That was not the case a few years ago when even professional teams would try to destroy a tower at level 1. It was fun, it was unusual and unpredictable. You should definitely try this trick with your friends :)
What forgotten mechanics do you still remember? Share your thoughts in comments.