Benjamin is a good Hero for Half Cash, due to his income, his life-healing, and his useful Trojan attacks (especially for beating the Round 40 MOAB). Obyn Greenfoot is also a viable option on harder maps due to his cheap cost and useful abilities for early-mid game.
Bonus Dart Monkey, Mana Shield, Military Conscription, Extra Cash, Hero Favors, and Pre-Game Prep are among the important MK to possess for Half Cash.
Once these MK are available to use, most maps on Half Cash can be completed without Powers by starting the game with a combination of the free Dart Monkey and half-discount Sub.
If necessary, using Insta-Monkeys can make beating the mode more trivial due to not costing any money.
The early rounds can be dangerous without proper Monkey Knowledge, as the player is given very little money to pop the bloons, especially the grouped blue rush on round 4. It is recommended to gain MK before attempting Half Cash.
Monkey Sub with the Naval Upgrades MK is extremely helpful for the first few rounds, as it will have 3-pierce homing darts.
Double Cash Mode returns bloon pop income to default values, practically making the game mode the same as playing on Standard Hard difficulty without Double Cash, minus the halved income from other sources (e.g. Banana Farms).
This gamemode previously used to be Half Starting Cash before update 2.0, where it was considered too trivial for Hard game setting and thus changed later.
Many have argued that Half Cash mode is harder than C.H.I.M.P.S. on easier maps mostly because of the lack of income to build defenses that would be much easier to build in C.H.I.M.P.S.
Monkey Bank capacity has not been halved, even though its production rate is halved (specifically the additional money added per round but not the interest rate)