Conditional Effects: Criticals
Probably one of my favourite layers for balancing/structuring at varied levels of play, Conditional Effects allow for increased Discoverability (embedded interactions players can/will discover over a varied amount of time) and Education of a playerbase, giving concrete elements for "upgrading" play a player of any level can consistently work on.
Critical Shots are probably the most recognizable of the concept; hitting crits in a game can help separate high level play from low, by offering further rewards for mechanical skill development (though it kinda feels like the options revolve mostly around doing extra damage? Maybe an occasional stun-effect), but imo represent one of the most boring standards that can also serve to really hamper further design expression throughout a game.
The added benefit of huge rewards for hitting Crits, can drive a lot of focus into only looking for mechanical depth (and often for huge damage value which eats up a lot of potential, more interesting design choices).
Are 2x modifiers still the standard? Multiplier chains? Are there examples of games that chain together varied effects? Larger damage > slower movement > stun effect for repeat triggers?
If specific characters could actively switch which effect shows up in the chain first, would there be more versatility in given playstyles?
Overall, the concept really lends itself to a lot of options if you're inventive enough.