I checked the flickering issue again and it it caused by firefox hardware acceleration, so nothing wrong with the game.
But I found a bug on strategy map on very hard skill level: When you return to Ben Dabi to meet your partner and to make him rejoin the squad after conquering the villages he indicated, the game crashes and reports a memory access error. This bug can be reproduced.
I am playing a campaign on very hard skill level and it is really hard, so don't get me wrong. If the enemy outnumbers me, there usually is no chance of winning the battle. Anyway sometimes the AI doesn't manage to defeat you when hiding your squad. They just stand around, try to fire at you but hardly ever hit, because your soldiers are well protected behind some objects. See these images:
7 enemies attacking 3 mercs armed only with light weapons. I tried to hide in the building some times but they came from everywhere and kicked my ass. So I restarted the battle some times and tried this place. For whatever reason the AI in this case doesn't try to attack from various sides. All enemies stay basically at the same spot and wait for me to take take them out.
My soldiers move one field towards the street, fire and hide again. The opponent's bullets all end up in that fence/wall where I am hiding. One remaining enemy approaching from the top comes too late.
This sometime occurs in buildings too. Normally the AI moves in quickly and kills your mercs. But sometimes it doesn't move in and tries to shoot through the windows from the outside. That makes it easy to kill them because the own mercs are protected by the building and the enemies are completely uncovered. Doesn't happen frecuently, but frecuent enough to restart the battle an win it after some try and error.
Suggestion: AI should notice that its soldiers are suffering severe damage while causing very little damage to the mercs. When the ratio is too bad for the AI, it should change its strategy and attack in a different way.
And another thought: The AI always attacks. I just have to wait for them to come for me with the advantage for me to kill some of them uncovered. The AI could use different strategies, for example hide in a building and wait for me to attack.