I just went back to play Plutonia Experiment after years of not playing it, and I managed to get through the first map of Plutonia on the first attempt. I've been tinkering with GZDoom and Doom Runner, and managed to murder my save games in the process, so I haven't gotten back to Legacy of Rust's second map, but I've tossed myself at it seven times and have yet to get very far in it. It's not a matter of ammo management with the second map on Legacy of Rust, it's just a heck of an ambush at the start.Is the difficulty similar to that of Plutonia Experiment? That one's first level had several chaingunners, revenants and mancubi, and very little ammo on hard difficulty. If you didn't seriously conserve it, there was no way to beat the level.
You're in a cavern-like area with little caves on the side, both ground level and elevated. You have shotgunners and imps in the ground level caves, and the new Lost Souls that shoot the fireballs in the elevated ones. Even when I make to through the ambush, I don't typically have enough health or knowledge to survive beyond that. There's also some pretty nasty traps beyond that ambush too, like a teleporter trap that puts you in a tiny room with about seven or so of those new Lost Souls.
I need to play through the first map again since I've lost that save, but I've been training my skills with the raven maps that Tim Willits made back in the day. By the way, I've also been trying those Doomworld Mega Project megawads, and those are a bitch compared to Plutonia.