- A.I. Breaker - Due to the vast number of special abilities in the game and their constantly changing nature, it's inevitable that there are a few that the beleaguered AI has trouble understanding. Examples include the tiger and snake's ambush ability, which the AI fails to understand only affect minions, and a predictable interaction between the AI's typical Attack! Attack! Attack! approach to strategy and the slime's Asteroids Monster ability.
- Game-Breaker: Many, many, many examples. Literally every update, a new one is introduced.
- Initially, the Phoenix Champion had no penalty. This led to spamming it, as it killed the attacker on Death. The Phoenixegg resulting from the Phoenix's death was eventually given a penalty.
- The Portal+++ Minion could teleport Champions to the 5th Rank. This allowed it to teleport Champions such as the Ninja and Valkyrie with Range 3 Unblockable Attacks to instantly checkmate the King.
- The Hauntedarmor+ Champion intially costed 10. This was the perfect Value to be resurrected by the Lifestone Minion, which initially had no Morale penalty, meaning that reviving a piece actually resulted in you having more morale than previously. This led to armies based around the strategy of using Hauntedarmor to trade with pieces until your opponent lost. Both of the pieces were given a nerf, with the Lifestone given a 4 morale penalty for reviving and the Hauntedarmor+, ++, and +++ given a cost increase, forcing players to use higher tier Lifestones.
- After that came the Phoenix Beacon strategy (also referred to as Bacon & Eggs, Breakfast, or Phobea [pronounced Phobia]), which dominated the game for over two months. It involved suiciding the Phoenix Champion into the enemy's units, and then recalling the resulting Phoenixegg with the Beacon Champion, and then waiting for it to revive, then repeating the process. It was widely considered unbeatable in the hands of a good player, which luckily did not include most of the users. Beacon was eventually changed to not be able to teleport Phoenixeggs, Saplings, or the King.
- After that was the Gravitymage Champion, a single piece that was considered by some to be the most overpowered piece ever released. It could pull units to its ability target, then Freeze the unit for 1 turn. What made it so powerful was that it could pull anything on the back row to its ability target 3 squares in front. From the back row. Which meant that you could kill 50% of your opponent's units, and they could literally do nothing about it. It was nerfed once, increasing its cost and Morale penalty to use and decreasing its pull range and ability target range. It wasn't enough. It was nerfed again, removing the Freeze and altering its ability target, rendering it completely useless.
- After that was the Reaver, a Minion that had superior coverage to most champions. It cost 1/2/3/4 at various tiers, and was supposedly balanced by paying morale on kill. However, most champions cost over 10. Do the math.
- At the same time, the Airelemental rose to prominence as the single best Champion in the game for area denial, as it had a long ranged ability to push units. When it pushed units, its value increased, giving you Morale. With pieces that use Morale to do things (e.g., the aforementioned Reaver or the Lich) you can win the game by massive margins with complete control of the board and a massive piece advantage.
- Memetic Mutation:
- Rescued from the Scrappy Heap: Despite being a cheap minion with excellent coverage and mobility, Mercenary was widely panned at its introduction due to its ability which caused it to switch sides every time it captured a piece. After having that ability changed so that it only swaps when taking champions, however, it sees some play as an expendable Minion with a strong moveset.
- Unexpectedly Realistic Gameplay: Mixed with Developers' Foresight in some of the interactions between pieces. For example, units with Freeze abilities destroy the [[Fireball]] unit.
YMMV / Chess Evolved Online