Thanks to the deleted saves after the last update, I replayed the game in Ironman and Realism. It is *so* much better. I didn’t save a single time and used only the checkpoint autosave to continue.
Because of some intrusive impulses on the last level, I entered Heinrich’s arena without Panzerfaust ammo, but it actually made things more interesting. I beat it after a few attempts—the best strategy for me was:
1. Start with the flamethrower (due to the lack of Panzerfaust) to burn the undead. If Panzer available, three shots are possible while crossing the distance between the portal and the arena.
2. Shoot with the Venom from mid-distance until it overheats (it’s better to learn how to avoid the sword hit after being pulled in by Heinrich’s telekinesis).
3. I had only one dynamite left when I started the level (again due to the urge to test the explosion radius on the previos level), and I was able to lure a new group of undead along with Heinrich over the blast. This cleared the undead and dealt good damage to the boss.
4. Side soldiers appeared, but don’t pay attention to them—they respawn almost immediately if killed. You can use the fire crates or the pillars as cover.
5. Take the health pack next to the pillar and use the Venom again. Switch back to the flamethrower for the undead.
6. Grab another health pack, or if it’s too far away and you’re low on health, use bandages or adrenaline. If using adrenaline, rush Heinrich and fire the Venom until it overheats.
7. Take the health pack next to the pillar again and use whatever ammo you have left in the Venom.
8. Use adrenaline/bandages and a shotgun from mid-distance. I also beat him using the BAR M1918A2 in my last session. The Itaca is a good option too, but it requires getting closer, which might not be ideal if you haven’t mastered “dancing” with the boss :)