Minuteman can indeed gain enough XP to level up - there's a green canister inside a container near the top right guard house.
Despite the description in

Rally the Troops actually boosts damage & knockback on the next attack. The effect is stronger on allies closer to Minuteman when he shouts, and is further augmented by 300 percenter. For reference, you can exploit this to make arcane bolt hit 90 on raptors in Prehistoric Panic and send them flying.
Liberty Lad's Tumble fixes his dodge chance to 1%. This bug exists across both

and

Law & Order's speed, blindness and jumper seem to get jumbled up.
Auto-cast © can be used to great effect in

with many characters, especially with Man-Bot using Transfer on auto-cast too. For example, liberty lad can lay an entire minefield in seconds, and man-o-war can rapid-fire Ball Lightning. Man-Bot can also lock down anything with auto energy leech, including Timemaster.
Most of the super expensive melee attacks in

are consistent, fast DPS and allow for your hero to slug it out against minions and bosses without planning ahead.
Rage prevents stun and dodging, making it ideal for landing slow but high knockback strikes. An enraged melee hero in the midst of enraged enemies can clean house on auto-pilot, even against tougher opponents.
That's it from me! What were your own observations and exploits from the games?