Heartrush is a bit map dependent and takes a different mindset to master. There are versions of heartrushing that are more/ less commitall i.e. do i want to throw everything in the wood chipper to try and heart rush win now or do i wanna play it safe and get heart hits where I can but always prepare to switch back if the pressure gets too much. Hydra is always used in the woodchipper variants so ill explain those. Im not a master of it by any means but the basic principles are this:
- before you make the push for heart rush, capture as many points as you can. Ideally you want all points to be captured before or during your push to the heart. saccing a couple 1 keys for this purpose works well, and depending on the map you can open with 3 1 keys to kinda force this playstyle really early.
- (the hard part) get a unit on the heart. It depends on the map what units you can get on the heart and how to go about this. Its not a one size fits all thing so its hard to give advice on it. But in general good heartrushing units have a very high amount of health and a good amount of damage, and hydra having both is obviously a good pick. Heart hitters dont have to be melee, in fact a few maps require ranged units to heart rush.
- Remove as much pressure from the opponent as you can by any and all means. Any way you can do this, do it. Debuff their units, put tanks in their way to block them off. Use gravedigger or garg walls to lock them out or even just the old fashioned method of removing pressure: just kill their stuff so they cant pressure you with it. This is the most important step. If youre good enough at this step you can actually get away with missing one of either step 1 or step 2. You can win via purely panic points or purely units on their heart provided that you stop your opponent pressuring you. If they cant hit the units attacking your heart or take back the points, they lose, so do whatever you can to not let them do it.