ZHEROS

To unlock this, you have to play through the entire game on medium. The DLC is included in this achievement for some reason, so you will have to buy it and play through eight more levels of fun. Even medium difficulty is kind of a nightmare to be honest, and in hindsight I should have probably played it on hard coop right away, and knocked out both of the character achievements on easy, but here we are.

I got through on by upgrading the gun first, fists second and shield last. The gun can clear out a room of small enemies when fully upgraded, which is immensely helpful and allows you to focus your fists on the larger enemies. I basically got by with spamming and cancelling the animation for the final attack in the combo by pressing , before starting a new combo a little faster than if the animation was played out. When the more powerful spamming combo is unlocked (....), use that instead. There are probably other helpful combo's for AoE or knockback, but I couldn't be bothered to remember them while playing. The shield is a life saver though! Always keep an eye out for shots to reflect or hits to block.

Towards the end of the game, careful planning of when to use the gun was key! Get a feel for the different encounters. It could be best to use the gun on the first wave in order to conserve your health for later waves. It could be much better to save it in order to halve the health of a later spawning lightning rod enemy. You might want to idle between rooms so that the gun can recharge. Experiment on which order to take out enemies in as well. Bosses are comparatively easy, but for 3-8 I had to avoid melee for the final half of the battle. My only option was to run around and avoid his laser while the gun reloaded.

Make sure to read the walkthrough of this game as well, it is full of useful strategies for enemies and levels.