Is something wrong with all 4 of the Optimization IDEs? When I go to https://www.codingame.com/ide/puzzle/code-vs-zombies (or Mars Lander or ...) there is an empty box at the centre-bottom, saying "Test cases Players" but nothing else.There is no list of Test cases to choose.I see this in Chrome and Firefox.
Also when I refresh the page, I see the Testcases appear very quickly before they disappear.
until they fix it you can just remove the div with the class cg-ide-agents-management directly
Julien is looking into it.