You can't adjust the difficulty from the menu.(Although, given the high demands on your funds, I'd suggest restarting from checkpoint if you die regardless) You'll have to restart from a checkpoint. If you die and don't have enough money, you will not be revived.
This "navigational aid" is disabled in 1999 Mode In lower difficulty levels, you can get a "hint" in the form of an arrow pointing towards your objective by pressing a button.This makes weapon upgrades slightly more important, but I honestly have had very few situations where I ran low on ammo, and with your "companion" handing you weapons, it doesn't seem like a big deal, honestly. It takes more shots to down an enemy, but bullets are somewhat more scarce.You still get a shield, but it takes fewer hits and recharges much, much slower.Checkpoints are similarly spaced, although I've been told there are extra ones before the Handymen (the really hard "boss" level enemies in the game).Any suggestion of "combat specializations" that must be tuned is puzzling. I haven't noticed a large difference in my money supply. The weapon and Vigor upgrades are identical and cost the same amount of money.The harder enemies are definitely the same, although the weaker ones are a bit too numerous to be compared easily.