Boss Bar Regeneration

Boss Bar Regeneration was an Event Only Mechanic that was introduced during the Summer 2013 Event and Fall 2013 Event. This mechanic introduce a more difficult form of battle in which players had to race against the clock to defeat Abyssal Boss Fleets as every hour that passed the Abyssal Boss Health Bar would gradually recover from the damage it took from your fleet.

Introduction

Back in the Summer 2013 Event the Boss Bar Regeneration mechanic was first introduced. This mechanic was used during the later stages of the event maps when confronting newly introduced boss abyssal at the time. The main function of this mechanic was that as you defeated a boss abyssal during your event run, the health bar would deplete, but after each hour that passed by, the boss bar would gradually regenerate a few % of overall HP at a time. At the later stages of the events the bar would regenerate much further than it would at early operation stages.

The mechanic would once more return in the Fall 2013 Event where the main function of the mechanics remained unchanged though to help compensate for the difficulty from the Summer 2013 Event the dev team made the health bar deplete as the boss abyssal took damage. However, regardless of these changes, this mechanic did not go well with players and resulted backlash.

Controversy

In both events, the boss regeneration bar mechanic received a negative response from fans as it was taxing among players to work with. Since there were situations where players would have to push themselves to work extensively to beat the boss fleet in one sitting rather than taking their time. It was quite possible for the Abyssal Boss to recover all of their HP in over the course of a few hours.

However, this wouldn't get full attention until the Fall 2013 Event where due to the night battle only mechanics, along with the Night to Day Battle Mechanic and the introduction of the first Installation Boss resulted in many players getting stuck or having a hard time beating the event map without making very unnecessary risks to do so....

Conclusion

Following the Fall 2013 Event in a magazine interview Kensuke Tanaka discussed a bit on his thoughts regarding the Fall 2013 Event. He explained that he didn't like how players were throwing away their kanmusus in battle like the way they were and made a conclusion in the same article that he was going to change things up in the future so players would not have to throw away their kanmusus in a meaningless fashion as was seen in the Fall 2013 Event. Since then the Boss regeneration Mechanic did not return to Kantai Collection since then.